Author: admin

  • How do I change my headlight globe?

    Quick answer

    Find the globe type in your owner’s manual (for example H4, H7 or H11), switch the lights off and let the globe cool, then reach in behind the headlight, remove the dust cover, release the clip or twist the globe out, and fit the new one without touching its glass. On many cars it’s a 10-minute job, but some modern cars need the bumper or headlight removed, and LED or HID headlights are a different job.

    Is this a DIY job?

    • Difficulty: Easy on many cars; Pro on cars that need the bumper, wheel arch liner or headlight unit removed
    • Time: 10 to 30 minutes when the globe is reachable
    • Tools: owner’s manual, clean gloves or a lint-free cloth, torch, sometimes a screwdriver or trim tool
    • Skills: working by feel in a tight space

    Open the bonnet and look behind the headlight before you buy anything. If you can see a round rubber or plastic cover on the back of the headlight and reach it with your hand, it’s usually a DIY job. If the back of the headlight is hidden behind the battery, air box or bumper, check the manual. It may say to remove other parts first, which is often a job for a workshop.

    Step by step

    1. Find the right globe. Look in the owner’s manual under “bulbs” or “lamps”. It lists each globe by type (e.g. H4, H7, H11, HB3, HB4). You can also read the type printed on the base of the old globe once it’s out.
    2. Check what kind of headlights you have. If your car has LED headlights or HID (xenon) headlights from the factory, stop here and read “When to call an auto electrician”. Many LED headlights don’t have a replaceable globe at all.
    3. Switch off and let it cool. Turn the headlights and ignition off. Halogen globes get very hot. Give them a few minutes.
    4. Open the bonnet and find the back of the headlight. You’re looking for a round dust cover on the back of the headlight housing, one for each globe position. The manual shows which cover is low beam and which is high beam.
    5. Make room if needed. On some cars you need to unclip the air intake duct or move the coolant reservoir aside. Only move parts the manual says to move.
    6. Remove the dust cover. Twist it anticlockwise or pull the rubber cover off.
    7. Unplug the globe. Pull the wiring connector straight off the back of the globe. Don’t pull on the wires themselves.
    8. Release the globe. Some globes are held by a wire spring clip: push it in and sideways to release it. Others twist out (usually anticlockwise) or have a locking ring. Note the way the old globe sits, including the tabs on its base.
    9. Fit the new globe without touching the glass. Hold it by the metal or plastic base. Skin oil on halogen glass creates a hot spot that can shorten its life or crack it. If you do touch it, wipe the glass with a lint-free cloth and a little methylated spirits or isopropyl alcohol and let it dry.
    10. Seat it the same way round. The tabs only fit one way. Make sure it sits flat before you refit the clip or twist it home. A globe that’s crooked will give a poor beam.
    11. Reconnect the plug and refit the dust cover. A missing or loose cover lets in water and dust.
    12. Test it. Check low beam and high beam on both sides. Then check the aim against a wall at night: if the new globe’s beam sits noticeably higher or lower than the other side, it probably isn’t seated properly.
    13. Consider doing both sides. Globes on both sides age at the same rate, so when one fails the other often isn’t far behind. Replacing them as a pair also keeps the light colour and brightness even.

    Specs table

    Common halogen headlight globe types (12V)

    Type Filaments Typical wattage Base Usually used for
    H4 2 (high and low beam in one globe) 60/55 W P43t Low and high beam in one headlight position
    H7 1 55 W PX26d Low beam or high beam (one function per globe)
    H11 1 55 W PGJ19-2 Low beam or fog lights
    HB3 (9005) 1 60 W P20d High beam
    HB4 (9006) 1 51 W P22d Low beam or fog lights

    Which globe goes where depends on the vehicle. Always confirm in your owner’s manual or from the old globe. Don’t fit a higher-wattage globe than specified: it can overheat the headlight and wiring.

    What you’ll need

    • H4 headlight globe / H7 headlight globe / H11 headlight globe (whichever your manual specifies; buy a pair)
    • nitrile gloves
    • dielectric grease (optional, a smear on the connector terminals helps keep moisture out)

    When to call an auto electrician

    • The manual says to remove the bumper, wheel arch liner or headlight unit to reach the globe.
    • Your car has factory LED headlights. Many are sealed units with no replaceable globe, and some have control modules.
    • Your car has HID (xenon) headlights. The igniter produces a very high voltage when the light switches on. Leave these to a professional.
    • The new globe doesn’t work, works only on one beam, or blows again quickly. That points to a wiring, connector, relay or control module fault.
    • A warning light or “lamp failure” message stays on after the change. Some cars with CAN-bus lighting systems are sensitive to the type of globe fitted.
    • The headlight lens is full of water or condensation that doesn’t clear.

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    Related questions

    Q: Why does my new headlight globe not work? A: Check it’s seated properly and the connector is fully on. Then check the fuse, and test the old globe in the other side if you can. If it still doesn’t work, the fault is probably in the wiring, relay or switch. (see How do I check and replace a blown fuse?)

    Q: Should I replace headlight globes in pairs? A: It’s a good idea. Both globes have done the same hours, and matching globes give an even colour and beam on both sides.

    Q: Can I fit brighter or LED globes? A: Halogen “performance” globes of the same type and wattage are designed as direct replacements. LED retrofit globes in halogen headlights raise legal and glare questions; that topic has its own article. Never fit a higher-wattage globe than your headlight is designed for.

    Q: Why do my headlights seem dim? A: Old globes dim with age, and cloudy or yellowed lenses cut light output. Poor earths and low charging voltage can also make lights dim.

    Q: Is it illegal to drive with one headlight out? A: A headlight that doesn’t work on high or low beam is a reason to reject a vehicle at a roadworthy inspection, and police can issue a defect notice or a fine. Penalties vary by state. Replace a failed globe as soon as you can.

    Sources

    1. HELLA, “Halogen bulbs” product information (2026) – 12V wattages and bases for H4 (60/55 W, P43t), H7 (55 W, PX26d) and H11 (55 W, PGJ19-2). https://www.hella.com/forvia-us/assets/documents/BI_Halogen_Bulbs_2026.pdf (checked October 2026)
    2. NARVA, “12V HB3 60W P20d halogen headlight globe” – HB3 rating and base. https://www.narva.com.au/products/48005 (checked October 2026)
    3. NARVA, “12V 51W P22d (9006) HB4A halogen globe” – HB4 rating and base. https://narva.com.au/products/narva-12v-51w-p22d-9006-hb4a-halogen-globe-box-of-1 (checked October 2026)
    4. NARVA, “How to replace a headlight globe” – let the globe cool, don’t touch the glass, check the manual for the globe type, replace in pairs. https://narva.com.au/narva-university/blogs/how-to-replace-a-headlight-globe (checked October 2026)
    5. NARVA, “Headlight globes – tech talk” – H4 is twin-filament, others single; higher-wattage globes than specified can damage wiring and the headlight; globe categories come from UN Regulation 37. https://narva.com.au/narva-university/blogs/headlight-globes-tech-talk (checked October 2026)
    6. Transport Tasmania, “Light Vehicle Inspection Manual – Reasons for Rejection” (V23) – a high or low beam headlamp that doesn’t work is a reason for rejection. https://transport.tas.gov.au/__data/assets/pdf_file/0011/402698/Light_Vehicle_Inspection_Manual_-Reasons_for_Rejection-_V23.PDF (checked October 2026)

  • Do I need a vehicle-specific towbar wiring harness?

    Quick answer

    On most modern vehicles, yes, it’s the safer choice. Many current cars and utes monitor the current in each rear light circuit and use it to detect bulbs and trailers. Splicing trailer wiring into the tail-light loom can trigger warnings, upset trailer detection features and risk damaging the body control module. A vehicle-specific harness plugs into the factory connectors without cutting, and usually includes a trailer module that powers the trailer lights separately. Older vehicles without electronic lamp monitoring can often use a universal kit.

    Is this a DIY job?

    • Difficulty: Medium (plug-in harness); Pro (vehicles needing coding or a module install behind trim)
    • Time: 1 to 2 hours for a plug-in harness
    • Tools: trim tools, socket set, multimeter or trailer tester, cable ties
    • Skills: removing boot or tray trim, routing wiring neatly

    How the options differ

    Option How it works Suits
    Vehicle-specific (plug-and-play) harness Plugs into factory tail-light connectors with matching plugs; a module reads the signals and drives the trailer lights from its own fused battery feed Most vehicles with CAN-bus or monitored lighting
    Universal kit with isolating module Taps into lamp wires; a module isolates the trailer load from the vehicle circuits Some vehicles, where the harness maker says it’s suitable
    Direct splice Trailer wires joined straight to tail-light wires Older vehicles without lamp monitoring only

    Step by step

    1. Check what your vehicle needs. Look in the owner’s manual, the towbar maker’s fitting guide or ask the harness supplier. Some vehicles also need a dealer or scan-tool setting to enable trailer mode.
    2. Choose the right harness. Match make, model, year and body type. Check whether it includes a 7-pin flat or 12-pin socket, and whether it has an electric brake signal output.
    3. Disconnect the battery negative if the instructions say to.
    4. Remove the trim to reach the tail-light connectors. Keep clips and screws together.
    5. Plug the harness in-line at each tail-light connector as instructed. Don’t cut factory wiring.
    6. Mount the module where the instructions say, away from water and heat.
    7. Run the power feed from the battery, fused near the battery, if the harness needs one. Route it away from exhaust and sharp edges, using grommets through panels.
    8. Fit the socket at the towbar with its cover and seal.
    9. Test every function with a trailer tester: tail, both indicators, stop, reverse, and brake output if fitted.
    10. Check for warnings on the dash. Then refit the trim.

    Specs table

    Signs a vehicle needs a module or plug-in harness

    Sign Why it matters
    Bulb or lamp-failure warnings on the dash The vehicle monitors lamp current
    LED tail lights from the factory Very low current; often monitored
    Trailer stability or trailer-detection features May rely on detecting a connected trailer
    Owner’s manual or towbar guide calls for a specific harness Follow the maker

    What you’ll need

    • towbar wiring harness (vehicle-specific)
    • 7 pin flat trailer socket or 12 pin flat trailer socket (if not included)
    • trailer circuit tester
    • inline fuse holder (if the harness needs a battery feed and doesn’t include one)
    • split loom tube and cable ties

    When to call an auto electrician

    • No plug-in harness exists for your vehicle.
    • The vehicle needs trailer mode enabled or a module coded.
    • You also need an electric brake controller, a 12-pin auxiliary circuit or a DC-DC charger.
    • Warnings appear after fitting, or the trailer lights behave oddly.

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    Related questions

    Q: Can I just splice into my tail lights? A: On older vehicles without lamp monitoring, a careful splice can work. On most modern vehicles it risks warnings, faults and problems with trailer detection, so a plug-in harness is the safer choice.

    Q: Does a towbar harness run electric trailer brakes? A: A lighting harness alone doesn’t. Electric brakes need a brake controller wired to pin 5. (see How do I install an electric brake controller?)

    Q: Will a towbar harness affect my warranty? A: A plug-in harness that doesn’t cut factory wiring is less likely to cause disputes than a spliced install. If you’re concerned, ask your dealer before fitting.

    Q: Why do my trailer lights work but the car shows a warning? A: The vehicle may be detecting an unexpected load on its lamp circuits. That usually means a splice or an incompatible module. Have it checked.

    Sources

    1. EV Parts 4×4, “GWM Cannon trailer wiring: dedicated vs universal” – example of a body control module monitoring lamp current; risks of splicing; plug-in harness with module (vendor article, one vehicle example). https://evparts4x4.com/blogs/featured-articles/gwm-cannon-trailer-wiring-dedicated-vs-universal (checked October 2026)
    2. Department of Infrastructure, VSB 1 Revision 5 – trailer connectors to AS 2513 or AS 4177.5; pin 5 of a 7-pin connector recommended for service brakes only. https://www.infrastructure.gov.au/sites/default/files/documents/vehicle-standards-bulletin-1-revision5-trailers-with-an-aggregate-trailer-mass-of-4-5-tonnes-or-less-june2009-pdf.pdf (checked October 2026)
    3. ARB, Hayman Reese CAN ECU module for towing systems – modern vehicles use CAN-bus networks, and a module manages trailer light and brake signals without upsetting vehicle systems or triggering dash warnings (manufacturer product page). https://www.arb.com.au/product/twle70029-hayman-reese-can-ecu-module-for-towing-systems (checked October 2026)

  • What does the battery light on my dashboard mean?

    Quick answer

    The red battery light usually means the car’s charging system has stopped charging, not that the battery itself is flat. The common causes are a broken or slipping drive belt, a failed alternator or regulator, or a loose or corroded connection. The car is now running on battery power alone and may stop without much warning, so switch off anything you don’t need and head straight for a safe place or help. If the temperature gauge rises too, stop: the same belt may drive the water pump.

    Is this a DIY job?

    • Difficulty: Easy to check; Medium to Pro to repair
    • Time: 10 to 20 minutes to check
    • Tools: torch, digital multimeter
    • Skills: basic multimeter use; care around a running engine

    You can do the first checks safely. Fixing the cause, such as replacing a belt or alternator, is a workshop job on many cars.

    Step by step

    1. If you’re driving, reduce the load. Switch off the air conditioning, heated seats, rear demister, radio and any accessories you don’t need. Keep the headlights on if you need them to be seen.
    2. Watch the temperature gauge. If it starts to rise, pull over safely and switch off. On many engines one belt drives both the alternator and the water pump.
    3. Don’t switch off until you’re somewhere safe. If the battery is low, the car may not restart. Head for home, a workshop, or a safe place to wait for roadside assistance.
    4. Look at the drive belt (engine off, key out). Check it’s still there, isn’t cracked, frayed or glazed, and isn’t covered in oil or coolant. A squeal when the light comes on often points to a slipping belt.
    5. Check the battery terminals and cables. Loose or corroded terminals can stop the charge reaching the battery. Check the main cable at the back of the alternator too, but don’t touch it with metal tools: it’s always live.
    6. Measure the charging voltage. Engine idling, everything off, multimeter across the battery. On most cars you’d expect roughly 13.5 to 14.8 V. Near or below battery voltage (about 12.6 V or lower) means it isn’t charging. Over about 15 V means it’s overcharging. Smart alternators can read lower at times. (see How do I know if my alternator needs replacing?)
    7. Note when the light comes on. At idle only, at high revs, after rain, with the A/C on, or flickering with the lights. This helps pinpoint the fault.
    8. Get it diagnosed. A charging fault won’t fix itself, and a new battery alone won’t fix it.

    Specs table

    What the battery light usually means

    When it happens Likely cause
    On steadily while driving Alternator not charging: belt, alternator, regulator or wiring
    On with a squeal, especially at start-up Slipping or worn belt
    On with rising engine temperature Broken belt (water pump may not be turning): stop
    Flickers at idle, goes out with revs Worn alternator, slipping belt or poor connection
    On after a jump start or battery change Sometimes a connection left loose; check terminals
    Comes on with several other warning lights Low system voltage affecting other modules
    On with ignition on, engine off Normal: it should go out once the engine starts

    Charging voltage at the battery (engine running, 12V systems)

    Reading Meaning
    About 13.5 to 14.8 V Normal charging (conventional alternator)
    About 12.6 V or less Not charging
    Above about 15 V Overcharging: get it checked promptly

    What you’ll need

    • digital multimeter
    • battery terminal brush
    • If needed: drive belt, alternator

    When to call an auto electrician

    • The light stays on with the engine running.
    • The voltage is too low or too high.
    • The belt has broken or keeps slipping.
    • Several warning lights came on at once, or electrical items act strangely.
    • It’s a hybrid or EV. These don’t have a conventional alternator; the 12V battery is charged by a DC-DC converter from the high-voltage system. That’s professional-only: never touch orange cables.

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    Related questions

    Q: How far can I drive with the battery light on? A: There’s no safe fixed distance. It depends on the battery’s charge and what’s switched on. Reduce the electrical load and go straight to a safe place or a workshop.

    Q: Will a new battery turn the light off? A: No. The light reports a charging fault. A new battery will just be drained in turn.

    Q: Why does the battery light come on and off? A: Intermittent faults are common with a slipping belt, worn alternator brushes or a loose connection. Get it checked before it fails completely.

    Q: Is it the battery or the alternator? A: If the voltage rises to normal charging levels with the engine running, the alternator is working and the battery may be the problem. If it stays at battery level, suspect the charging system. (see Is it my starter motor or my battery?)

    Sources

    1. RACV, “What do the car dashboard symbols and warning lights mean” – battery/charging light points to the charging system (alternator, wiring, drive belt); get it checked immediately. https://www.racv.com.au/royalauto/transport/cars/what-do-the-car-dashboard-symbols-mean-and-warning-lights.html (checked October 2026)
    2. JS Alternators, “How to test your alternator” – charging voltage ranges and smart alternators. https://js-alternators.com/blogs/blog/how-to-test-alternator (checked October 2026)
    3. NRMA, “What do my dashboard warning lights mean” – red warning lights. https://mynrma.com.au/cars-and-driving/car-servicing/resources/what-do-my-dashboard-warning-lights-mean (checked October 2026)

  • How do I read fault codes with an OBD2 scanner?

    Quick answer

    Find the 16-pin diagnostic port under the dash on the driver’s side, plug in the scanner (or a Bluetooth adaptor paired to an app), switch the ignition on and choose “read codes”. Write down every code and any freeze-frame data before you do anything else. A code tells you which system has seen a problem, not which part to replace, and clearing it doesn’t fix the fault.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 5 to 15 minutes to read; longer to research what the codes mean
    • Tools: OBD2 code reader or Bluetooth OBD2 adaptor with a phone app, pen and paper (or phone camera), owner’s manual
    • Skills: following on-screen menus

    Anyone can read engine codes. Working out the cause, and anything to do with airbags, ABS or hybrid systems, is a job for a professional with a full diagnostic tool.

    Which cars have an OBD port?

    Australian Design Rule 79/01 brought in on-board diagnostic (OBD) requirements for light vehicles (up to 3.5 t GVM). It applied to all petrol vehicles built from 1 January 2006 and all diesel vehicles built from 1 January 2007. New models were covered a year earlier: petrol from 2005, diesel from 2006. As first made, the rule exempted vehicles running on LPG or natural gas (including dual-fuel) from the OBD part. Many earlier cars also have the port, but what a generic scanner can read on them varies.

    Australian rules follow the European version of OBD (often called EOBD). It uses the same 16-pin connector and the same generic code format as the American OBD2 system, so a standard OBD2 scanner works on most of these cars.

    Step by step

    1. Park safely. Park on level ground, handbrake on, in Park or neutral. Don’t use the scanner while driving.
    2. Find the port. Look under the dash on the driver’s side, usually near the steering column, behind the fuse panel cover or near the bonnet release. If you can’t find it, check the owner’s manual.
    3. Plug in with the ignition off. Push the scanner or adaptor in firmly. It only fits one way.
    4. Switch the ignition on. Turn the key to “on” (or press start without your foot on the brake) so the dash lights up. Some scanners also work with the engine running. Follow the scanner’s instructions.
    5. Connect the app (Bluetooth adaptors only). Pair the adaptor with your phone and open the app. Choose your vehicle if the app asks.
    6. Read the codes. Choose “read codes” or “DTCs”. Note whether each code is stored (confirmed), pending, or permanent, if the scanner shows that.
    7. Record everything. Write down or photograph every code, its description and any freeze-frame data (engine speed, temperature and so on when the fault was set). This is the evidence a technician needs.
    8. Check readiness monitors. Many scanners have an “I/M readiness” or “monitor status” screen. It shows which emission self-tests have finished. Record it too.
    9. Look up the codes. Use the scanner’s built-in library or the vehicle maker’s information. Read the code as “where to start looking”, not “replace this part”. A code for an oxygen sensor, for example, can be caused by a wiring fault, an air leak or a fuel problem.
    10. Don’t clear the codes yet. Clearing turns the light off but doesn’t repair anything. It also wipes the freeze-frame data and resets the readiness monitors. If the fault is still there, the light will come back.
    11. Unplug the scanner with the ignition off. Don’t leave a Bluetooth adaptor plugged in long-term unless it’s designed for it. Some keep drawing power and can flatten the battery. (see Why does my car battery keep going flat?)

    Specs table

    Reading a fault code (for example P0301)

    Position What it tells you Values
    1st character System P = powertrain (engine, transmission, emissions); B = body (airbags, air conditioning, seats); C = chassis (ABS, steering, suspension); U = network (communication between control modules)
    2nd character Who defined the code 0 = generic code, same meaning on every make; 1 = manufacturer-specific code, meaning set by the vehicle maker
    3rd to 5th characters The specific fault Look up the full code for the exact meaning

    Codes beginning with other second digits (2 or 3) exist too. Whether they’re generic or manufacturer-specific depends on the code range, so look them up rather than assuming.

    What the engine warning light is telling you

    Light What it usually means What to do
    Comes on and stays on The OBD system has detected a fault Read the codes and get it checked soon
    Flashing A serious fault, such as a misfire that can damage the catalytic converter Avoid high speed and heavy loads; get it checked as soon as possible
    Went out by itself The system no longer sees the fault Codes may still be stored; read them at your next chance

    Generic scanner vs professional diagnostic tool

    Job Basic OBD2 reader or Bluetooth adaptor Professional diagnostic tool
    Read and clear generic engine codes (P0) Yes Yes
    Live engine data and readiness monitors Often Yes
    Manufacturer-specific engine codes Sometimes Usually
    Airbag/SRS, ABS, body and network modules Rarely (some readers cover ABS and airbag codes on certain makes) Usually
    Hybrid and EV high-voltage systems No Needs maker-level tools and training
    Coding, resets and calibrations after repairs No Often

    A generic OBD2 connection is mainly limited to engine and emissions data. Reaching the other modules, running tests and doing relearns or coding needs an enhanced or maker-level tool.

    What you’ll need

    • OBD2 code reader or Bluetooth OBD2 adaptor
    • OBD2 extension cable (if the port is hard to reach)

    When to call an auto electrician

    • The engine warning light is flashing, or the car is running badly.
    • The airbag/SRS or ABS warning light is on. These are safety systems: don’t clear the codes or drive on assuming it’s fine. Airbag work is professional only.
    • The car is a hybrid or EV. High-voltage systems are professional only, and their faults need maker-level diagnostic tools.
    • The code points to wiring, a network (U) fault or several modules at once.
    • The light keeps coming back after a repair.
    • You need the car to pass a roadworthy. Roadworthy inspections don’t read the car’s computer, but they do check that warning lights such as the engine, ABS and airbag lights go out after start-up, and they include a brake test. Clearing codes just before an inspection doesn’t fix anything, and the light is likely to come back on.

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    Related questions

    Q: Does clearing a fault code fix the problem? A: No. Clearing only turns the warning light off and erases the stored data. If the fault is still there, the code and the light will come back, and the information a technician would have used is gone.

    Q: Can I use a cheap Bluetooth OBD2 adaptor? A: For reading generic engine codes and live data, often yes. They usually can’t read airbag, ABS or most body modules, so they won’t show every fault on the car.

    Q: Why won’t my scanner connect? A: Check the ignition is on, the plug is fully seated and the scanner supports your vehicle. A blown fuse feeding the diagnostic port can also stop it powering up. (see How do I check and replace a blown fuse?)

    Q: What are readiness monitors? A: They’re self-tests the engine computer runs on emission systems such as the catalytic converter and oxygen sensors. Clearing codes or disconnecting the battery resets them, and they only complete after the car has been driven through the right conditions.

    Q: Is a diagnostic scan worth paying for? A: If the light keeps returning, or the fault involves airbags, ABS or hybrid systems, a professional scan goes much deeper than a basic reader.

    Sources

    1. Federal Register of Legislation, Vehicle Standard (Australian Design Rule 79/01 – Emission Control for Light Vehicles) 2005 – applies to M1 and N1 vehicles up to 3.5 t GVM; petrol new models from 1 January 2005, all petrol vehicles from 1 January 2006; diesel new models from 1 January 2006, all diesel vehicles from 1 January 2007; OBD requirements and the exemption for LPG and natural gas (mono-fuel and bi-fuel) vehicles (clause 5.5). https://legislation.gov.au/F2005L04080/asmade/2005-12-15/text/original/pdf/1 (checked October 2026)
    2. Vehicle Service Pros, “Different types of diagnostics: an overview of scan tool options” – basic code readers and generic OBD-II are limited to engine/emissions data; enhanced tools add ABS, SRS and other modules, bidirectional tests, coding and relearns. https://www.vehicleservicepros.com/distribution/tool-distributor/article/12066051/different-types-of-diagnostics-an-overview-of-scan-tool-options (checked October 2026)
    3. US Environmental Protection Agency, “On-Board Diagnostics (OBD) – Check Engine Light” fact sheet (EPA420-F-02-016) – steady vs flashing warning light; light turns off by itself when the fault is corrected; scan tool connects under the dash. https://19january2021snapshot.epa.gov/sites/static/files/2013-08/documents/420f02016.pdf (checked October 2026)
    4. New York State DMV, “What do you mean my car’s not ready?” – readiness monitors; clearing codes with a scan tool or disconnecting the battery leaves monitors incomplete; drive cycles. https://dmv.ny.gov/brochure/what-do-you-mean-my-cars-not-ready (checked October 2026)
    5. Haynes, “OBD fault codes” – first letter P, B, C, U system meanings; second character 0 generic, 1 manufacturer-specific. https://uk.haynes.com/de/pages/odb-fault-codes-car (checked October 2026)
    6. SAE J1962 / ISO 15031-3 (standard) – 16-pin diagnostic connector located within reach of the driver’s seat.
    7. Bosch (OTC), OBD 1200 code reader product sheet – reads ABS and airbag/SRS codes on certain makes and years only. https://otctools.com/sites/default/files/102019_145_obd_1200_bosch.pdf (checked October 2026)

  • How much do auto electricians charge in Australia?

    Quick answer

    Published Australian cost guides checked in October 2026 put auto electrician labour at roughly $90 to $180 an hour, with metro rates generally higher than regional ones. Common jobs range from a couple of hundred dollars for a battery supplied and fitted, to anywhere from a few hundred to over $1,000 for an alternator or starter motor. Prices vary a lot by location, vehicle and fault, so get a written quote for your car.

    Is this a DIY job?

    • Difficulty: Not applicable (this is a cost guide)
    • Time: 10 minutes to gather the details for a quote
    • Tools: your car’s make, model, year and VIN; photos of any warning lights
    • Skills: none

    Some jobs in this guide, like swapping a battery or a globe, are easy to do yourself. Others, like diagnosing an intermittent fault or fitting a brake controller, are better left to a professional. Each master article in this library has an “Is this a DIY job?” section to help you decide.

    What affects the price

    1. Location. Metro rates are generally higher than regional rates, though regional jobs can add travel.
    2. Mobile or workshop. Mobile services save you a tow or a trip, and may charge a call-out fee. A workshop may have better equipment for complex faults.
    3. The vehicle. European, luxury, hybrid and EV models often take longer and need specialist tools or software. Parts can cost more.
    4. Parts. New, reconditioned or genuine parts all cost differently. Ask which is being quoted.
    5. Diagnosis time. A simple fault may take minutes to find. An intermittent fault or a drain that only appears overnight can take hours.
    6. Access. A battery under the bonnet is quick. An alternator or starter buried under other parts takes much longer.
    7. When you need it. After-hours, weekend and emergency call-outs usually cost more.

    Step by step: getting an accurate price

    1. Describe the problem clearly. What happens, when it started, whether it’s constant or comes and goes, and any warning lights or noises.
    2. Give your vehicle details. Make, model, year, engine and VIN. Mention modifications (dual battery, lights, towbar wiring).
    3. Send photos. A photo of the dash with the warning light on, and of any visible damage, helps.
    4. Ask how they charge. Is it a fixed price, an hourly rate, or a diagnostic fee first? Is there a call-out fee? Does the price include GST?
    5. Ask about parts. New or reconditioned? What warranty comes with the parts and the labour?
    6. Get it in writing. Ask for a written quote or estimate, and ask to be contacted before any extra work is done.
    7. Compare like with like. A cheaper quote may use different parts or exclude diagnosis. Check what’s included before you compare.

    Specs table

    Published price ranges (checked October 2026)

    These figures come from published Australian cost guides and quote platforms, not from a formal industry survey. They’re a starting point for budgeting, not a quote. Unless noted, prices include parts and labour.

    Item Price range found Source and date
    Hourly labour, general $90 to $150 per hour ServiceTasker cost guide, updated February 2026
    Hourly labour, South Australia About $110 to $180 per hour The Quote Yard, June 2026
    Hourly labour, mobile auto electricians (average) About $128 per hour ServiceSeeking, May 2026
    Hourly labour, metro vs regional $120 to $150 metro; $90 to $120 regional ServiceTasker, updated February 2026
    Standard call-out fee (urban) $50 to $100 ServiceTasker, updated February 2026 (one source)
    After-hours or emergency work $130 to $250 per hour ServiceTasker, updated February 2026 (one source)
    Electrical diagnostic or scan $90 to $250 The Quote Yard (SA), June 2026
    Battery: standard battery only $120 to $180 Yellow Pages, updated May 2026
    Battery: premium (e.g. AGM) battery only $185 to $450 Yellow Pages, updated May 2026
    Battery supplied and fitted, standard $150 to $400 ServiceTasker, updated February 2026
    Alternator replacement $200 to $500 ServiceTasker, updated February 2026
    Alternator or starter motor replacement $400 to $1,500 The Quote Yard (SA), June 2026
    Wiring or fault repair $150 to $900 The Quote Yard (SA), June 2026
    Air conditioning regas or repair $150 to $1,500 The Quote Yard (SA), June 2026
    Accessory fit-out (dual battery, lights) $300 to $2,500 The Quote Yard (SA), June 2026
    Hybrid or EV high-voltage diagnostic $150 to $600 The Quote Yard (SA), June 2026

    Real fixed-price examples (Melbourne, July to October 2026)

    Listed fixed quotes on a booking platform, including GST, for specific vehicles. They show how much prices vary with the vehicle.

    Job Vehicle Listed price
    Alternator replacement (plus belt and extras) 2010 Toyota RAV4 $602
    Alternator replacement (plus extras) 2006 Mercedes-Benz Sprinter $789
    Starter motor replacement (plus extras) 2007 Mazda 3 $397
    Starter motor replacement 2007 Mercedes-Benz B-Class $967
    “Vehicle will not start” inspection Two vehicles $99 and $188

    Why the alternator ranges differ: the lower figures may not include all parts, or may reflect a simple car with easy access. The higher figures cover harder-to-reach units, newer or European vehicles, and new rather than reconditioned parts.

    What you’ll need

    Nothing to buy for a quote. If you decide to do a simple job yourself, the parts are listed in each master article, for example:

    • car battery
    • OBD2 code reader
    • digital multimeter

    When to call an auto electrician

    • You have a warning light, no-start or electrical fault you can’t trace with simple checks.
    • The job involves airbags/SRS, hybrid or EV high-voltage systems, or air conditioning refrigerant. These are professional-only. Refrigerant work must be done by someone holding a refrigerant handling licence from the Australian Refrigeration Council (ARCtick).
    • You’re adding accessories that draw high current: dual batteries, inverters, brake controllers, winches.
    • Your car is under warranty and you want the work documented. According to the ACCC (as reported by CHOICE), you don’t have to use the dealer to keep the manufacturer’s warranty, as long as the work is done by qualified people to the manufacturer’s specifications with suitable parts. Keep your invoices. Some extended warranties have their own conditions.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

    Find an auto electrician near you

    Related questions

    Q: Do auto electricians charge for diagnosis? A: Many do, either as a fixed diagnostic fee or by the hour. Finding a fault takes time and equipment. Ask up front how diagnosis is charged and whether it comes off the repair bill if you go ahead.

    Q: Is a mobile auto electrician more expensive? A: Not always. Some charge a call-out fee, but you save on towing and time. For complex faults, a workshop with more equipment can sometimes be quicker overall.

    Q: Can I get a quote over the phone? A: For simple jobs like a battery or a known part, often yes. For faults, a firm price usually needs a diagnosis first, because the same symptom can have several causes. (see Can I get a quote for an auto electrical problem?)

    Q: Do auto electrician prices include GST? A: It depends on the business. Always ask whether a quote includes GST so you can compare quotes fairly.

    Q: How can I keep the cost down? A: Describe the fault clearly, note when it happens, and take photos of warning lights. Keep the battery healthy and terminals clean, and fix small problems before they turn into bigger ones.

    Sources

    1. ServiceTasker, “How much do auto electricians charge per hour? Cost guide 2026” – hourly, call-out, after-hours, battery and alternator ranges. Updated February 2026. https://servicetasker.com.au/cost-guides/how-much-do-auto-electricians-charge-per-hour (checked October 2026)
    2. ServiceSeeking, “Mobile auto electrician prices in Australia 2026” – average hourly rate. Published May 2026. https://www.serviceseeking.com.au/pricing/mobile-auto-electrician-prices-in-australia-2026 (checked October 2026)
    3. The Quote Yard, “Auto electrician SA – typical costs” – SA labour rate and job ranges. Published June 2026. https://www.thequoteyard.com.au/services/auto-electrician-sa (checked October 2026)
    4. Yellow Pages, “How much does a car battery cost?” – battery price ranges and fitting cost. Updated May 2026. https://www.yellowpages.com.au/articles/mechanics-and-motor-engineers/price-of-car-battery-replacement (checked October 2026)
    5. AutoGuru, mobile auto electrician listings (Melbourne) – fixed-quote examples, July to October 2026. https://www.autoguru.com.au/auto-electrician/vic/melbourne/central-park/mobile (checked October 2026)
    6. Australian Refrigeration Council, “What type of licence do I need?” – automotive air conditioning work and refrigerant handling need an ARC refrigerant handling licence (automotive). https://www.arctick.org/licensing/licence-types/ (checked October 2026)
    7. CHOICE, “Car warranties and dealer servicing” – quotes the ACCC on servicing outside the dealer network. https://www.choice.com.au/transport/cars/servicing/articles/car-warranties-and-dealer-servicing (checked October 2026)

  • Where should the fuse go when wiring an accessory?

    Quick answer

    Put the fuse in the positive cable as close to the battery (or other power source) as practical, so almost none of the cable is left unprotected. Rate the fuse at or below what the cable can safely carry, and above what the accessory normally draws. The fuse’s job is to protect the cable from overheating if it shorts to the body, which is why it belongs at the source end, not at the accessory.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 15 to 45 minutes, depending on access to the battery
    • Tools: spanners for the battery terminals, crimp tool, wire stripper, multimeter, cable ties
    • Skills: basic crimping and reading a current rating

    Fitting a fuse holder is straightforward. Get help if you’re feeding high-current gear (inverters, winches, DC-DC chargers), working on a vehicle with a battery monitoring sensor on the negative terminal, or wiring anything in a hybrid or electric vehicle.

    Step by step

    1. Work out the accessory’s current. Check its label or manual for amps. If it only lists watts, divide by 12 for a rough figure (for example, 120 W ÷ 12 V = 10 A).
    2. Size the cable first. Choose cable by copper area in mm² for the current and run length. The fuse is chosen to suit the cable, so this comes first. (see What size cable do I need for my 12V accessory?)
    3. Pick the fuse rating. It must be above the accessory’s normal draw (including any start-up surge the maker mentions) and at or below the cable’s current rating. If the accessory maker specifies a fuse, use that, as long as it’s no higher than the cable can carry.
    4. Pick the fuse type. Getting the protection right matters more than anything else in this job, because it’s what stops cable damage and fires. Blade fuses suit most small accessories. Higher currents need MIDI or ANL fuses, or a circuit breaker (see the table below). Under the bonnet, under the vehicle or anywhere it can get wet, use a waterproof (sealed) fuse holder or circuit breaker. A circuit breaker can be reset instead of replaced, which suits accessory circuits that may trip occasionally.
    5. Disconnect the battery. Negative terminal off first, then you can work near the positive safely.
    6. Mount the fuse holder close to the battery. Fix it firmly, away from sharp edges, exhaust heat and moving parts, and where you can reach it to check or replace the fuse. The short cable between the battery and the fuse is the only unprotected part, so keep it as short as you practically can and protect it with loom tube.
    7. Connect the battery side. Use a properly crimped lug on the battery positive terminal or an approved power stud. Don’t stack lots of lugs on one terminal.
    8. Run the cable to the accessory. Use loom tube, grommets through any metal panel, and secure it every so often so it can’t rub through.
    9. Run a proper earth. Use a negative cable of the same size back to the battery or a clean, solid chassis earth point.
    10. Fit the fuse last. With everything connected and checked, fit the fuse, then reconnect the battery: negative on last.
    11. Test. Switch the accessory on and confirm it works. Check that nothing, including the fuse holder, gets warm after a few minutes of running.

    Two power sources, two fuses. If a cable can be fed from both ends, such as the link cable between a main and an auxiliary battery, or the feed to a DC-DC charger, fit a fuse or circuit breaker near each battery. A short anywhere along the cable is then cut off from both sides. (see How does a dual battery system work and do I need one?)

    Specs table

    Common fuse and breaker types for 12V accessories

    Type Typical ratings Notes
    Standard or mini blade fuse Up to 40 A Colour-coded by rating; plugs into an inline holder or fuse block
    MIDI (bolt-down) fuse 30 to 200 A (32 V DC) Time-delay type that tolerates short surges; the maker states 150 to 200 A sizes are for short-circuit protection only
    ANL fuse 35 to 750 A Bolt-on, for heavy cables such as inverter and winch feeds
    Circuit breaker, Type I (auto reset) Various Resets itself and keeps cycling until the fault clears
    Circuit breaker, Type II (modified reset) Various Stays open while power is applied; resets when power is removed
    Circuit breaker, Type III (manual reset) Various Stays off until you press the reset button or lever

    For accessory feeds, a manual-reset (Type III) breaker is usually the safer choice, because it stays off until someone looks at why it tripped.

    Blade fuse colours

    Rating Colour
    5 A Tan
    7.5 A Brown
    10 A Red
    15 A Blue
    20 A Yellow
    25 A Clear (natural)
    30 A Green
    40 A Orange

    Maxi fuses use a different colour code. Always go by the number printed on the fuse.

    Matching fuse to cable (examples)

    Cable ratings from one Australian cable maker, for a single cable at 30°C. Ratings drop with heat and bundling, so in an engine bay choose a fuse well under the figure.

    Cable sold as Copper area Maker’s rating at 30°C Fuse must be no higher than
    3mm auto cable 1.13 mm² 20 A 20 A, lower in hot spots
    4mm auto cable 1.84 mm² 28 A 28 A, lower in hot spots
    6mm auto cable 4.59 mm² 48 A 48 A, lower in hot spots

    Fuses come in set ratings, so choose the nearest standard size at or below the limit. Twin-core and bundled cables have lower ratings than single-core; check the figure for the exact cable you buy.

    Other brands rate the same sizes much lower. For example, some 3mm auto cable sold in Australia is rated at 10 A, and some 4mm twin-core at 15 A. Go by the rating printed on the cable or packet you actually buy, and if in doubt use the lower figure.

    What you’ll need

    • inline blade fuse holder (waterproof type under the bonnet)
    • blade fuses
    • MIDI fuse holder or ANL fuse holder (high-current feeds)
    • manual reset circuit breaker
    • fuse block (if you’re adding several accessories)
    • cable lugs and crimp terminals
    • split loom tube and rubber grommets
    • auto cable (sized for the job)

    When to call an auto electrician

    • The accessory draws high current (inverter, winch, air compressor, DC-DC charger) or needs cable heavier than 6mm auto cable.
    • The vehicle has a battery sensor on the negative terminal, a smart alternator, or a stop-start system. Adding loads in the wrong place can upset charging. (see What is a smart alternator and how does it affect accessories?)
    • You’re adding several accessories and need a fused distribution block or auxiliary battery.
    • Fuses keep blowing. That usually points to a short or a fault, not a fuse that’s too small.
    • The vehicle is a hybrid or EV (high-voltage systems are professional-only), or the wiring runs near airbags or SRS looms.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

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    Related questions

    Q: Should the fuse go near the battery or near the accessory? A: Near the battery. A short can happen anywhere along the cable, and only the part after the fuse is protected.

    Q: Can I use a bigger fuse so it stops blowing? A: No. A fuse rated higher than the cable lets the cable overheat before the fuse blows. Find out why it’s blowing instead.

    Q: Does the negative cable need a fuse? A: In a normal negative-earth vehicle, the fuse goes in the positive cable only. The negative is at earth potential, so a short to the body doesn’t draw current through it.

    Q: Can I tap into the vehicle’s fuse box instead? A: For small loads, a fuse tap on a suitable circuit can work. Stay within that circuit’s rating and avoid safety circuits such as airbags.

    Q: Fuse or circuit breaker: which is better? A: Both protect the cable. A breaker can be reset after a trip; a fuse is cheaper and simpler. For high currents, choose a type rated for the job.

    Sources

    1. Tycab, automotive cable catalogue – low tension single-core cable by stranding, with copper areas and current ratings at 30°C (14/0.32 1.13 mm² 20 A; 23/0.32 1.84 mm² 28 A; 57/0.32 4.59 mm² 48 A) and temperature derating. https://www.tyree.nz/wp-content/uploads/2019/09/Automotive-Comp.pdf (checked October 2026)
    2. Littelfuse, ATO and MAXI blade fuse datasheet (via Farnell) – blade fuse colour codes by rating; maxi colour code differs. https://www.farnell.com/datasheets/82316.pdf (checked October 2026)
    3. Littelfuse, MIDI 498 series datasheet – 32 V DC, 30 to 200 A, time-delay; 150 to 200 A for short-circuit protection only. https://www.enika.eu/data/files/Littelfuse_MIDI_0498_auto32V.pdf (checked October 2026)
    4. Eaton Bussmann, ANL low-voltage limiter fuse datasheet – 35 to 750 A, 32 V AC / 80 V DC. https://static.chipdip.ru/lib/651/DOC044651693.pdf (checked October 2026)
    5. Littelfuse, aftermarket circuit breakers catalogue – Type I automatic reset, Type II modified reset, Type III manual reset definitions. https://www.littelfuse.com/~/media/automotive/datasheets/circuit-breakers/littelfuse_aftermarket_circuit_breakers.pdf (checked October 2026)
    6. Narva, 3mm single core cable – sold as 3mm and rated 10 A. https://narva.com.au/products/narva-10a-3mm-white-single-core-cable-100m (checked October 2026)
    7. Wiltronics, 4mm twin core auto cable – 23/0.32 stranding, 1.85 mm², rated 15 A. https://www.wiltronics.com.au/product/52830/4mm-twin-core-auto-cable (checked October 2026)

  • How do I jump start a car safely?

    Quick answer

    Connect red to the flat battery’s positive, red to the good battery’s positive, black to the good battery’s negative, and the last black clamp to bare metal on the flat car’s engine or body, away from the battery. Start the good car, wait a few minutes, then start the flat car. Remove the leads in the reverse order. Check your owner’s manual first: some cars have dedicated jump points, and some hybrids and EVs have specific rules.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 10 to 20 minutes
    • Tools: jumper leads (heavy duty) or a portable jump starter, safety glasses, gloves, owner’s manuals for both cars
    • Skills: following a sequence carefully

    Jump starting is a normal roadside job, but getting the order wrong can cause sparks, damage electronics or, rarely, make a battery explode. Take your time.

    Step by step

    Jump start lead connection order Step 1: red clamp to the flat battery positive. Step 2: other red clamp to the good battery positive. Step 3: black clamp to the good battery negative. Step 4: last black clamp to bare metal on the flat car’s engine or body, away from the battery. Remove in reverse order. Jump starting: connect in this order Car with the flat battery + − Flat battery Engine Bare metal bolt, away from battery Car with the good battery + − Good battery 1 2 3 4 1 Red to flat + 2 Red to good + 3 Black to good − 4 Black to bare metal on flat car Remove in reverse: 4, 3, 2, 1. Check your owner’s manual for jump points, especially on hybrids, EVs and cars with the battery in the boot.
    Jump start lead connection order
    1. Check the manuals. Find the jump points for both cars. Some cars have remote jump terminals under the bonnet because the battery is in the boot or under a seat. Check whether either car is a hybrid or EV and what the manual allows.
    2. Check the batteries. Don’t jump start if either battery is cracked, leaking, swollen or badly corroded. Both systems must be the same voltage (almost all cars are 12V).
    3. Position the cars. Bring the good car close enough for the leads to reach, without the cars touching. Handbrakes on, automatics in Park, manuals in neutral. Both ignitions fully off, and switch off lights, radio and A/C.
    4. Protect yourself. Safety glasses and gloves on, rings and metal watch bands off. No smoking or flames. Keep leads away from fans and belts.
    5. Connect red to the flat battery’s positive (+).
    6. Connect the other red clamp to the good battery’s positive (+).
    7. Connect black to the good battery’s negative (−).
    8. Connect the last black clamp to bare metal on the flat car, such as an unpainted bolt or bracket on the engine, well away from the battery and moving parts. Don’t connect it to the flat battery’s negative post: the final connection can spark, and batteries can give off hydrogen gas.
    9. Start the good car and let it run for a few minutes.
    10. Start the flat car. Crank for no more than about 5 seconds at a time. If it doesn’t start, wait a couple of minutes before trying again. If it still won’t start after a few tries, the problem may not be the battery. (see Is it my starter motor or my battery?)
    11. Remove the leads in reverse order: black from the flat car’s earth point, black from the good battery, red from the good battery, red from the flat battery. Don’t let the clamps touch each other or any metal.
    12. Keep the jumped car running for a while, then have the battery charged properly and tested. Driving alone often won’t fully recharge a flat battery, and a battery that went flat for no clear reason may be failing or have a drain. (see Why does my car battery keep going flat?)

    Using a portable jump starter

    Follow the pack’s instructions. Most connect red to positive and black to an earth point or the negative post, with built-in reverse-polarity protection. Keep packs charged and stored out of direct sun, and avoid leaving lithium packs in a hot parked car. Don’t use a pack that is swollen, damaged or overheating.

    Specs table

    Connection order

    Step Clamp Connect to
    1 Red Flat battery positive (+)
    2 Red Good battery positive (+)
    3 Black Good battery negative (−)
    4 Black Bare metal earth point on the flat car, away from the battery

    Removal order: 4, 3, 2, 1 (the reverse).

    What you’ll need

    • jumper leads heavy duty or portable jump starter
    • safety glasses
    • smart battery charger (to recharge the battery properly afterwards)

    When to call an auto electrician

    • Either battery is damaged, leaking, swollen or smells of rotten eggs.
    • The car won’t start even with a good jump.
    • The car needs jump starting regularly.
    • Warning lights stay on after the car starts.
    • You’re not sure where to connect on a hybrid, EV or car with a battery in the boot. Never connect to or touch high-voltage parts or orange cables. Don’t use a hybrid or EV as the donor car unless its manual says that’s allowed.
    • If you’re not confident, call your roadside assistance provider.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

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    Related questions

    Q: Why not connect the last clamp to the flat battery’s negative post? A: The last connection often makes a small spark. Batteries can give off hydrogen gas, so the spark should happen away from the battery, on bare metal on the engine or body.

    Q: How long should I leave the car running after a jump start? A: Long enough to be sure it keeps running, then have the battery charged with a proper charger and tested. A short drive won’t fully recharge a flat battery.

    Q: Can I jump start a hybrid? A: Usually, yes, using the 12V jump points shown in the manual. The 12V battery powers up the system; you’re not jump starting the high-voltage battery. Follow the manual exactly.

    Q: Can jump starting damage my car? A: Done correctly, it rarely does. Reverse polarity, clamps touching, or connecting with ignitions on can damage electronics. Some vehicle manuals give specific warnings, so check yours.

    Sources

    1. RACV, “Car battery guide: how they work, when to replace them, and how to jump-start” – connection order; last clamp on unpainted metal on the flat car, not the flat battery’s negative; remove in reverse order. https://www.racv.com.au/royalauto/transport/cars/car-battery-guide-how-to-know-if-it-needs-replacing.html (checked October 2026)
    2. RAC (UK), “How to jump start a car in 10 steps” – crank limits, damaged battery warnings, hybrid donor caution. https://www.rac.co.uk/drive/advice/car-maintenance/how-to-jump-start-a-car/ (checked October 2026)
    3. ACCC Product Safety Australia, “Lithium-ion batteries guide” – store out of direct sunlight, not in hot places such as parked vehicles; don’t use swollen or damaged batteries. https://www.productsafety.gov.au/consumers/be-safe-around-the-home/safely-use-batteries-and-technology/lithium-ion-batteries-guide (checked October 2026)

  • How do I replace an indicator globe?

    Quick answer

    If one side’s indicator suddenly flashes fast, a globe on that side has usually blown. Find the globe type in your owner’s manual (often PY21W, P21W or WY5W), reach the globe holder from behind the lamp, twist it out, fit the new globe and test before you put everything back. Front indicators on some modern cars are reached through the wheel arch or need the headlight removed.

    Is this a DIY job?

    • Difficulty: Easy (rear and side indicators); Easy to Pro (front, depending on the car)
    • Time: 10 to 30 minutes
    • Tools: owner’s manual, screwdriver or trim tool, torch
    • Skills: gentle handling of plastic clips

    Rear indicators are usually reached from the boot, the same way as the brake lights. Side repeaters on the guards often pop out with a gentle push and twist. Front indicators vary the most: some twist out from behind the headlight, some are reached through an opening in the wheel arch liner, and some need the bumper or headlight removed.

    Step by step

    Common bayonet globe bases: BA15s, BAY15d and BAU15s Three 15 mm bayonet globes. BA15s (for example P21W): two locating pins opposite each other at the same height and one contact on the bottom. BAY15d (for example P21/5W): pins at different heights and two contacts on the bottom, so it only fits one way. BAU15s (for example amber PY21W): pins at the same height but not opposite each other, and one contact. Bayonet globe bases: how to tell them apart Side view (top row) and looking at the bottom of the base (bottom row). Not to scale. BA15s Pins level, opposite BAY15d Pins at different heights BAU15s Pins level, not opposite One contact Two contacts One contact, offset pin e.g. P21W (brake, reverse) e.g. P21/5W (brake + tail) e.g. PY21W (amber indicator) Always confirm the globe code in your owner’s manual or on the old globe before buying.
    Common bayonet globe bases: BA15s, BAY15d and BAU15s
    1. Work out which globe is out. Switch on the hazard lights and walk around the car. Check front, rear and side repeaters. A blown globe usually makes the dash indicator light and the ticking flash about twice as fast on that side.
    2. Find the globe type. Check the owner’s manual. Indicators commonly use PY21W (amber glass, bayonet), P21W (clear glass, for amber lenses), or small WY5W wedge globes in side repeaters. Buy a pair.
    3. Switch off. Ignition and lights off.
    4. Rear indicator: open the boot, remove the access cover or tail light unit as your manual shows, then twist the indicator holder out (usually anticlockwise).
    5. Side repeater: many slide or push one way to release a clip, then tilt out. Don’t lever against the paint; use a plastic trim tool and a cloth. Pull the holder out of the back and replace the wedge globe.
    6. Front indicator: look behind the headlight for a holder with an amber globe. If it isn’t reachable, check the manual. Some cars have an access flap in the wheel arch liner (turning the steering wheel gives more room). If the manual says to remove the bumper or headlight, consider a workshop.
    7. Remove the old globe. Bayonet: push in, twist anticlockwise, pull out. Wedge: pull straight out.
    8. Match the colour. If the lamp lens is clear, the globe must be amber (PY21W or WY5W). If the lens is amber, a clear globe (P21W or W5W) is normally used. An indicator must show amber light.
    9. Fit the new globe. PY21W globes have offset pins and only fit one way. Don’t force them.
    10. Test before refitting. Check the indicator flashes at the normal rate on both sides, then refit the holder, covers and lamp unit with seals in place.

    Specs table

    Common indicator globe types (12V)

    Type Glass Wattage Base Typical use
    PY21W Amber 21 W BAU15s (pins offset, one contact) Front and rear indicators behind clear lenses
    P21W Clear 21 W BA15s (pins level and opposite) Indicators behind amber lenses
    WY5W Amber 5 W Wedge (W2.1×9.5d) Side repeaters behind clear lenses
    W5W Clear 5 W Wedge (W2.1×9.5d) Side repeaters behind amber lenses

    Fitment varies by vehicle. Your owner’s manual or the old globe has the correct code.

    What you’ll need

    • PY21W amber indicator globe or P21W globe (front and rear, as specified)
    • WY5W amber wedge globe or W5W wedge globe (side repeaters)
    • plastic trim tool
    • If you’re converting to LED: LED flasher relay or load resistor (see related questions)

    When to call an auto electrician

    • The front indicator needs the bumper or headlight removed.
    • A new globe doesn’t fix the fast flashing, or no indicator on one side works at all. Check the fuse, then suspect the wiring, earth or switch.
    • The indicators don’t work at all, or the hazard lights work but the indicators don’t (or the reverse). That points to the flasher, switch or body control module.
    • Your car shows a “lamp failure” or bulb warning after the change, or you’ve fitted LED globes and get warnings. Many modern cars monitor lamp current through a CAN-bus control module, and the fix depends on the vehicle.
    • The indicator lamp is a sealed LED unit.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

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    Related questions

    Q: Why are my indicators flashing fast? A: Usually a globe has blown on that side. If you’ve fitted LED indicator globes, they draw so little current that the car thinks a globe is out. (see Why are my indicators flashing fast?)

    Q: Can I use a clear globe behind a clear indicator lens? A: No. The light from an indicator must be amber. Behind a clear lens you need an amber globe such as a PY21W or WY5W.

    Q: Why does my amber indicator globe look pale or flash white? A: The amber coating on cheaper globes can fade over time. Replace faded globes, because the light must still be amber.

    Q: Do I need to replace indicator globes in pairs? A: It isn’t essential, but the other side has done the same hours and often fails soon after. Replacing both keeps the colour matched.

    Sources

    1. OSRAM, PY21W product data – BAU15s base, 12 V, 21 W. https://osram.com/ecat/Lamps%20with%20metal%20bases-Signal%20lamps-Car%20lighting-Automotive/ae/en/GPS01_1057060/ZMP_60924 (checked October 2026)
    2. OSRAM, P21W product data – BA15s base, 12 V, 21 W. https://osram.com/ecat/Lamps%20with%20metal%20bases-Signal%20lamps-Car%20lighting-Automotive/gb/en/GPS01_1057060/ZMP_1285824 (checked October 2026)
    3. OSRAM, WY5W product data – W2.1×9.5d wedge base, 12 V, 5 W. https://www.osram.co.uk/ecat/gb/en/GPS01_1057061/ZMP_4057277 (checked October 2026)
    4. Federal Register of Legislation, Vehicle Standard (Australian Design Rule 13/00 – Installation of Lighting and Light Signalling Devices on other than L-Group Vehicles) 2005 – Table 1 lists direction-indicator lamps as amber. https://www.legislation.gov.au/F2005L03991/latest (checked October 2026)
    5. Federal Register of Legislation, Vehicle Standard (Australian Design Rule 6/00 – Direction Indicators) 2005 – component rule for direction indicators. https://www.legislation.gov.au/F2005L03907/latest (checked October 2026)

  • What size cable do I need for my 12V accessory?

    Quick answer

    Cable size depends on two things: the current the accessory draws and the total length of the cable run (there and back). At 12V, even a small voltage loss matters, so long runs need much thicker cable than you’d expect. Always compare cable by its copper area in mm², not its “mm” label: a cable sold as “6mm auto cable” has roughly 4.6 mm² of copper, not 6 mm². Then fuse the cable close to the battery so the fuse protects the cable.

    Is this a DIY job?

    • Difficulty: Medium
    • Time: 15 minutes to work out
    • Tools: accessory’s current rating (from its label or manual), tape measure, the table below
    • Skills: simple maths

    Step by step

    1. Find the current. Check the accessory’s label or manual for amps (A). If it only gives watts, divide by 12 for a rough figure (for example, 60 W ÷ 12 V = 5 A).
    2. Measure the run. Measure the one-way distance from the battery (or fuse block) to the accessory, along the route the cable will actually take.
    3. Decide the acceptable voltage drop. Many installers aim to lose no more than about 3% (around 0.36 V on a 12V system). Charging circuits such as DC-DC chargers and fridges often perform better with less: check the maker’s instructions, which usually specify a cable size.
    4. Look up the table below. Find your current and pick a cable whose maximum length is longer than your one-way run.
    5. Check the cable’s current rating. The table only covers voltage drop. The cable must also be rated for the current: use the ratings table below or the maker’s figure, and reduce it for heat and bundling.
    6. Choose the fuse. Fit a fuse or circuit breaker close to the battery, rated to protect the cable (at or below the cable’s rating) and suitable for the accessory. (see Where should the fuse go when wiring an accessory?)
    7. Use twin-core or a proper return. The negative needs the same size as the positive if it runs back to the battery. A thin earth wire undoes a thick positive cable.

    Specs table

    Auto cable labels, copper area and current rating

    The “mm” in an auto cable’s name is roughly its outside size, not its copper. What carries the current is the conductor cross-section in mm². Tycab, a major Australian cable maker, publishes these figures for its single-core auto cable:

    Sold as Stranding Copper area Tycab current rating at 30°C
    3mm auto cable 14/0.32 1.13 mm² 20 A
    4mm auto cable 23/0.32 1.84 mm² 28 A
    5mm auto cable 36/0.32 2.90 mm² 37 A
    6mm auto cable 57/0.32 4.59 mm² 48 A

    Heavier cable (B&S)

    B&S is the Australian name for the American wire gauge (AWG) sizes, but Australian battery cable is often made a little lighter than the true AWG area. Compare mm², not the gauge number.

    Size True AWG area Tycab battery cable area Tycab current rating at 30°C
    8 B&S 8.37 mm² 7.71 mm² 74 A
    6 B&S 13.3 mm² 13.5 mm² 103 A
    4 B&S 21.2 mm² 20.26 mm² 135 A
    2 B&S 33.6 mm² 32.07 mm² 188 A
    0 B&S 53.5 mm² 49.0 mm² 246 A

    Ratings drop with heat and bundling. Tycab’s ratings are for a single cable at 30°C. In hotter places, multiply by Tycab’s derating factor: 0.9 at 40°C, 0.76 at 50°C, 0.60 at 60°C and 0.45 at 70°C. A 6mm cable rated at 48 A carries only about 29 A in a 60°C engine bay. Cables bundled together in a loom lose more again. Twin-core cable is rated lower than single-core of the same size for the same reason; check the rating for the exact cable you buy.

    Maximum one-way run for about 3% voltage drop at 12V (copper, 20°C)

    Cable 5 A 10 A 20 A 30 A 50 A 100 A
    3mm auto (1.13 mm²) 2.4 m 1.2 m too small too small too small too small
    4mm auto (1.84 mm²) 3.9 m 1.9 m 1.0 m too small too small too small
    5mm auto (2.90 mm²) 6.1 m 3.0 m 1.5 m too small too small too small
    6mm auto (4.59 mm²) 9.6 m 4.8 m 2.4 m 1.6 m too small too small
    8 B&S (8.37 mm²) 17.5 m 8.8 m 4.4 m 2.9 m 1.8 m too small
    6 B&S (13.3 mm²) 27.8 m 13.9 m 7.0 m 4.6 m 2.8 m too small
    4 B&S (21.2 mm²) – 22.2 m 11.1 m 7.4 m 4.4 m 2.2 m
    2 B&S (33.6 mm²) – – 17.6 m 11.7 m 7.0 m 3.5 m
    0 B&S (53.5 mm²) – – 28.0 m 18.7 m 11.2 m 5.6 m

    How the table is worked out: voltage drop = current × resistance of the full loop (out and back). Copper resistance is about 0.0172 ohm per metre for 1 mm² at 20°C. Real cable gets warmer and loses a little more. B&S rows use the true AWG area; Tycab’s slightly lighter battery cable gives runs up to about 8% shorter at 8 B&S and 0 B&S. “Too small” means the current is at or above the cable’s rating, or leaves no margin for heat (for example 3mm cable rated at 20 A carrying 20 A, 5mm rated at 37 A carrying 30 A in a warm engine bay, or 6 B&S rated at 103 A carrying 100 A). “–” means the cable is far bigger than needed.

    What you’ll need

    • twin core auto cable (size from the table)
    • heavy duty single core auto cable (for high-current runs)
    • cable lugs and crimp terminals
    • inline fuse holder / circuit breaker / MIDI fuse holder
    • split loom tube and firewall grommet

    When to call an auto electrician

    • The run is long and the current is high (DC-DC chargers, inverters, winches, caravan charging).
    • You’re not sure what the accessory draws, or it has high start-up current (compressors, fridges, inverters).
    • Cable or terminals are getting hot, or accessories cut out under load.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

    Find an auto electrician near you

    Related questions

    Q: Is “6mm” cable 6 mm²? A: No. In Australian auto cable, “6mm” usually describes the outside diameter including insulation. The copper area is about 4.6 mm². Always compare mm².

    Q: Why does my fridge cut out when I’m driving or camping? A: Often because the cable is too thin for the length, so the voltage at the fridge drops below its cut-out setting. Thicker cable or a shorter run usually fixes it.

    Q: Can I use thicker cable than I need? A: Yes. Thicker cable has less voltage drop and runs cooler. It costs more and is harder to route, but there’s no electrical downside.

    Q: Does the negative cable need to be as thick as the positive? A: Yes, if it carries the same current back to the battery. The voltage drop happens on both sides of the circuit.

    Sources

    1. Solar4RVs, “Understanding cable size types: mm, mm², B&S, AWG” – auto cable “mm” is outside diameter; 3mm/4mm/6mm copper areas; B&S to mm² conversions; heat derating note (AS/NZS 3008). https://www.solar4rvs.com.au/buying/buyer-guides/understanding-cable-size-types-mm-mm2-b_s-awg/ (checked October 2026)
    2. Tycab, automotive cable catalogue – single-core auto cable (ASC) and battery cable (ABC) stranding, mm², current ratings at 30°C and temperature derating factors. https://www.tyree.nz/wp-content/uploads/2019/09/Automotive-Comp.pdf (checked October 2026)
    3. HS Auto Parts, “Tycab cable – how to select the right gauge” – Tycab battery cable B&S sizes, mm² and rating guide. https://hsautoparts.com.au/tycab-cable-selection-guide/ (checked October 2026)
    4. Technical review, Ozautoelectrics (October 2026) – compare cable by conductor cross-section in mm²; “3mm” auto cable is 1.13 mm².
    5. Resistivity of copper (about 1.72 × 10⁻⁸ ohm-metre at 20°C), standard physical constant used to calculate the voltage-drop table.

  • How do I check and replace a blown fuse?

    Quick answer

    Switch the ignition off, find the right fuse using the chart in your owner’s manual or on the fuse box lid, pull it out with the fuse puller, and look through the plastic: a broken metal strip means it’s blown. Replace it with a fuse of exactly the same rating (the number on top and the colour). If the new fuse blows again, there’s a fault in that circuit that needs finding: never fit a bigger fuse.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 5 to 15 minutes
    • Tools: owner’s manual, fuse puller (often clipped inside the fuse box), torch, test light or multimeter (optional)
    • Skills: none

    Checking and replacing a blade fuse is one of the simplest car jobs. Finding why a fuse keeps blowing is harder and may need an auto electrician.

    Step by step

    Blade fuse colour chart and how to spot a blown fuse Left: a good blade fuse with an unbroken metal strip, and a blown fuse with a broken strip. Right: standard blade fuse colours by rating: 1 A black, 2 A grey, 3 A violet, 4 A pink, 5 A tan, 7.5 A brown, 10 A red, 15 A blue, 20 A yellow, 25 A clear, 30 A green, 40 A orange. Maxi fuses use a different colour code. Blade fuses: good or blown, and the colour code 10 Good Unbroken strip 10 Blown Gap or blackened strip Replace with the same rating Never fit a higher-rated fuse. If it blows again, there’s a fault in that circuit. Regular, mini and micro blade fuses 1 A Black 2 A Grey 3 A Violet 4 A Pink 5 A Tan 7.5 A Brown 10 A Red 15 A Blue 20 A Yellow 25 A Clear 30 A Green 40 A Orange Maxi fuses use a different colour code For example 50 A maxi = red, 60 A maxi = blue. Always read the number printed on the fuse.
    Blade fuse colour and rating chart, and how to spot a blown fuse
    1. Switch off. Ignition off, key out, and switch off the item that stopped working.
    2. Find the fuse boxes. Most cars have at least two: one under the bonnet and one inside the cabin (under the dash, in the side of the dash, or behind a panel in the footwell or glovebox). Some have more, including one in the boot. Your owner’s manual shows where.
    3. Find the right fuse. Use the chart in the manual or on the inside of the fuse box lid. Fuses are labelled by position, rating and the circuit they protect (for example “CIG”, “RADIO”, “P/W”).
    4. Pull the fuse out. Use the plastic fuse puller, or fine-nose pliers, gripping the plastic body. Pull straight out.
    5. Check it. Hold it up to the light. A good fuse has an unbroken metal strip between the two blades. A blown fuse has a gap or a melted, blackened strip. If you can’t tell, test it: with a multimeter on continuity or resistance, a good fuse reads close to zero ohms. Many blade fuses also have small test points on top, so you can test them in place with a test light (ignition on for circuits that are only live with the ignition).
    6. Fit an identical replacement. Same type (micro, mini, standard or maxi), same rating (number on top), same colour. Push it fully into the slot.
    7. Test the circuit. Switch on and check the item works.
    8. If it blows again straight away, stop replacing fuses. There’s a short circuit or an overload in that circuit.
    9. Replace your spare. Many fuse boxes have spare fuses clipped inside. Replace any you use.

    Checking a relay

    Relays are the larger plug-in cubes in the fuse box. They switch high-current items like headlights, horns, fans and fuel pumps. A simple check: with the ignition off, swap the suspect relay with an identical relay (same part number) from a circuit you can test, such as the horn. If the fault moves with the relay, the relay is faulty. If you’re not sure two relays are identical, don’t swap them. (see How do I wire a 12V relay (pins 30, 85, 86, 87)?)

    Specs table

    Standard blade fuse colours (regular, mini and micro blade fuses)

    Rating Colour
    1 A Black
    2 A Grey
    3 A Violet
    4 A Pink
    5 A Tan
    7.5 A Brown
    10 A Red
    15 A Blue
    20 A Yellow
    25 A Clear (natural)
    30 A Green
    40 A Orange

    Not every rating is made in every size, but where a rating exists the colour is the same.

    Maxi fuses use a different colour code. For example, a 50 A maxi fuse is red and a 60 A maxi is blue. Always go by the number printed on the fuse, not just the colour.

    Fuse types by size

    Type Typical use
    Micro2 / Micro3 Many newer vehicles
    Mini blade Most cars from the 1990s on
    Standard (ATO/ATC) blade Older cars, many accessories and trailers
    Maxi blade High-current circuits under the bonnet
    Bolt-in or cartridge fuses Main supply and high-current circuits (leave to a professional)

    What you’ll need

    • mini blade fuse kit / standard blade fuse kit / micro blade fuses (whichever your car uses)
    • fuse puller
    • 12V test light or digital multimeter
    • automotive relay (if a relay has failed; match the part number)

    When to call an auto electrician

    • A fuse blows again after replacement. There’s a short or overload to find.
    • The blown fuse protects the airbags/SRS, ABS, engine management or a module. Don’t keep replacing these: get the fault diagnosed.
    • A large bolt-in, cartridge or main fuse has blown. These protect major circuits and often point to a serious fault.
    • Fuses, relays or the fuse box show signs of melting or heat damage.
    • It’s a hybrid or EV and the fault involves the high-voltage system. Never touch orange cables or high-voltage fuses.

    Need an auto electrician? Find local auto electricians and mobile services in your city.

    Find an auto electrician near you

    Related questions

    Q: Can I use a higher-rated fuse if I don’t have the right one? A: No. The fuse protects the wiring. A higher-rated fuse can let the wiring overheat and start a fire before the fuse blows. Never replace a fuse with wire, foil or any other metal object, even to get home.

    Q: Can I use a fuse from another circuit temporarily? A: Only if it’s exactly the same rating and from a circuit you don’t need, such as the cigarette lighter. Replace it with the correct fuse as soon as you can, and never borrow from safety systems.

    Q: Why does my fuse look fine but the circuit doesn’t work? A: Fuses can crack internally where you can’t see it, so test it with a multimeter or test light. If the fuse is fine, check the relay, switch, wiring and the item itself.

    Q: Where’s my car’s fuse box? A: Most cars have one under the bonnet and one in the cabin, and some have one in the boot. The owner’s manual shows the locations and what each fuse does.

    Sources

    1. Littelfuse, ATO and MAXI blade fuse datasheet (via Farnell) – blade fuse colour codes by rating; maxi colour code differs. https://www.farnell.com/datasheets/82316.pdf (checked October 2026)
    2. ISO 8820-3 – Road vehicles, fuse-links, Part 3: fuse-links with tabs (blade type). Referenced as the standard behind the colour code; not quoted.
    3. Volvo Cars Australia, “Replacing a fuse” (V90 owner information) – replace with the same colour and amperage; a higher-rated fuse or a foreign object can damage the electrical system and cause a fire. https://www.volvocars.com/au/support/car/v90/article/97f7da007063b1e3c0a8015164d3df7a/ (checked October 2026)
    4. Kia owner’s manual, “Fuse replacement” – same rating only; a fuse that blows again means an electrical problem; never use wire or foil in place of a fuse. https://ownersmanual.kia.com/full_webhelp/KA4/2024/en_US/topics/t00732.html (checked October 2026)