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  • How do I replace an interior light globe?

    Quick answer

    Switch the interior light off, gently prise the clear lens off with a plastic trim tool, and pull the old globe out. Most interior lights use either a festoon globe (a small tube with a cap at each end) or a W5W (T10) wedge globe. Fit a new one of the same type and size, test it, and clip the lens back on.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 5 to 15 minutes
    • Tools: plastic trim tool (or a small flat screwdriver wrapped in tape), clean cloth
    • Skills: a gentle touch with plastic clips

    This is one of the easiest jobs on a car. The main risks are scratching or cracking the lens, and pulling on wiring in the roof lining.

    Step by step

    1. Switch the light off. Set the interior light switch to off (not “door”), so it doesn’t come on while you work. The globe can be hot if it’s been on.
    2. Find the notch. Most lenses have a small slot or notch on one edge for a trim tool. The owner’s manual usually shows where.
    3. Prise the lens off gently. Slide the trim tool into the notch and lever carefully. Work around the edge rather than forcing one point. Keep the lens: they crack easily.
    4. Identify the globe. – Festoon: a glass tube with a metal cap at each end, held between two spring clips. – Wedge (W5W / T10): a small glass globe with a flat plastic or glass base that pushes straight in. – Small bayonet (e.g. R5W/R10W): twists out like a brake light globe. – LED module: a circuit board with no separate globe. These usually aren’t serviceable.
    5. Remove the old globe. Festoon: lift one end out of its clip with a fingernail or trim tool, then the other. Wedge: pull straight out. Bayonet: push, twist anticlockwise, pull out.
    6. Match the size. Festoon globes come in several lengths. Measure the old one end to end in millimetres, or read the size printed on the cap, and buy the same length.
    7. Fit the new globe. Festoon: push it between the clips so it’s held firmly at both ends. If it’s loose, gently squeeze the clips closer together. Wedge: push it straight in.
    8. Test it. Switch the light on. If you’ve fitted an LED and it doesn’t light, take it out, turn it around (or rotate the wedge 180 degrees) and try again: many LEDs only work one way round.
    9. Refit the lens. Line up the tabs and press it home until it clicks.

    Specs table

    Common interior globe types (12V)

    Type Shape Typical wattage Base Typical use
    W5W (T10, US 168) Small wedge 5 W W2.1×9.5d Map lights, boot lights, number plates, side markers
    C5W Festoon 5 W Festoon caps (36 mm is common; other lengths exist) Dome lights, boot lights
    R5W Small bayonet 5 W BA15s Some older interior and number plate lamps

    Festoon globes come in several lengths. Always match the length of the old globe. Your owner’s manual lists the types for your car.

    What you’ll need

    • festoon globe (matching length) or W5W T10 wedge globe
    • plastic trim tool
    • Optional: LED festoon or LED T10 wedge (see related questions)

    When to call an auto electrician

    • The new globe doesn’t work and the fuse is fine. Check the door switches and wiring, or have it tested.
    • The interior light stays on with the doors shut, or comes on by itself. That can flatten the battery. (see Why does my car battery keep going flat?)
    • The light is in a roof console near the A-pillars or a sunroof and you’d need to remove the console. Curtain airbag wiring and modules can be nearby.
    • The light is an LED module with no separate globe.

    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 put LED globes in my interior lights? A: In most cars, yes, and they run cooler and draw less power. If the light flickers or glows faintly when off, the car may be checking the circuit with a small current. A CAN-bus-rated LED may fix it.

    Q: Why won’t my LED interior globe work? A: Most LEDs only work one way round. Turn it around and try again.

    Q: Why does my interior light stay on? A: The light switch may be set to “on”, a door, boot or bonnet switch may be faulty, or a door may not be fully latched. Check each door switch.

    Q: How do I know which festoon size to buy? A: Measure the old globe from end to end, or check the size printed on its cap. Common lengths vary, so don’t guess.

    Sources

    1. Wikipedia, “List of automotive light bulb types” – W5W, C5W and R5W base types and wattages; W5W ANSI equivalent 168. https://en.wikipedia.org/wiki/List_of_automotive_light_bulb_types (checked October 2026)
    2. Narva, “12V 5W T-10 W5W wedge globe” product page – 12V 5W, W2.1 x 9.5d base, ECE R37 category W5W; used for park, interior, number plate and side marker lamps. https://www.narva.com.au/products/47501BL/12v-5w-w2-1-x-9-5d-w5w-wedge-globes–blister-pack-of-2- (checked October 2026)
    3. Narva, “12V 5W SV8-5.8 C5W festoon globes” product page – 12V 5W C5W festoon, 11 x 36 mm. https://www.narva.com.au/products/47254BL (checked October 2026)

  • Can I get a quote for an auto electrical problem?

    Quick answer

    Yes. For a known job, like a battery, a globe or an accessory install, most auto electricians can give a firm price over the phone or online if you supply your vehicle details. For a fault, such as a no-start, a warning light or a battery that keeps going flat, you’ll usually get a price for diagnosis first, then a firm quote for the repair once the cause is found. The more detail and photos you give, the more accurate the quote.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 10 to 15 minutes to gather the details
    • Tools: phone camera, notepad, your registration papers or the car’s compliance plate
    • Skills: none

    Why faults often need diagnosis first

    The same symptom can have several causes. A car that won’t start could need a new terminal clamp, a battery, a starter motor or an immobiliser repair. A fair auto electrician won’t guess. Expect one of these:

    • Fixed-price job: the work and parts are known (battery fitted, trailer plug wired, reversing camera installed).
    • Diagnostic fee, then quote: a set fee or time to find the fault, then a written quote for the repair.
    • Estimate with a range: a likely cost with a clear limit, and a promise to call you before going over it.

    Step by step

    1. Write down your vehicle details. Make, model, year, engine and transmission. The VIN is on your registration papers and usually on a plate in the engine bay or at the base of the windscreen.
    2. Describe the problem in plain words. What happens, what doesn’t, and what you hear, see or smell.
    3. Say when it happens. Every time, or only sometimes? Cold or hot engine? After rain? Only when it’s been parked overnight? Intermittent faults take longer to find, so these details save time and money.
    4. Note any history. Recent battery change, jump start, accident, new accessories, or work done by someone else.
    5. Take photos. The dashboard with warning lights on (engine running if safe), any damaged or corroded parts, and any aftermarket wiring. A short video helps with noises.
    6. If you have codes, include them. If you’ve read fault codes with an OBD2 reader, send the exact codes. (see How do I read fault codes with an OBD2 scanner?)
    7. For installs, describe what you want. For example: dual battery with a DC-DC charger and where the second battery goes; brake controller with the trailer’s details; or reversing camera with or without a new screen.
    8. Ask the right questions. How is diagnosis charged? Is there a call-out fee? Does the price include GST? What warranty applies? Will they contact you before extra work?
    9. Get it in writing. A written quote protects both of you. It should list the work, parts, labour and how long the price is valid. An estimate is only a best guess, so ask to be called before the cost goes over an agreed limit.
    10. Compare like with like. Check each quote covers the same parts, scope and warranty.

    Specs table

    What to send with a quote request

    Item Example
    Vehicle 2016 Toyota Hilux 2.8 diesel, auto
    VIN From rego papers or compliance plate
    Problem Battery goes flat after 3 days parked
    When Started after a new stereo was fitted last month
    Warning lights None (photo attached)
    Codes None read
    Where the car is Suburb or postcode; can it be driven?
    What you want Find and fix the drain; quote before repair

    What you’ll need

    No parts to buy. If you’d like to read engine codes yourself before calling:

    • OBD2 code reader
    • digital multimeter (to note your battery voltage)

    When to call an auto electrician

    • Straight away if a red warning light is on, you smell burning, or the car is unsafe to drive. Don’t drive it to a workshop if the oil pressure, temperature or brake warning lights are on: ask about mobile service or towing. (see What should I do when a warning light or fault code comes up on my dashboard?)
    • When simple checks haven’t found the fault.
    • For any work involving airbags/SRS, hybrid or EV high-voltage systems, or air conditioning refrigerant.

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

    Find an auto electrician near you

    Related questions

    Q: Why won’t an auto electrician give me a firm price over the phone? A: Because the same symptom can have several causes. A firm price before diagnosis would either be a guess or padded to cover the worst case. A diagnostic fee followed by a firm quote is usually fairer.

    Q: Is a diagnostic fee taken off the repair price? A: Some businesses deduct it if you go ahead with the repair, others don’t. Ask before you book.

    Q: How many quotes should I get? A: For a large install or an expensive repair, two or three written quotes are reasonable. For a diagnosis, it’s usually better to pick one business and let them find the fault.

    Q: How much do auto electricians charge? A: Rates vary by location and job. See the researched ranges in the cost guide. (see How much do auto electricians charge in Australia?)

    Sources

    1. NSW Government, “Consumer guarantees” – services must be provided with acceptable care and skill and deliver agreed results. https://www.nsw.gov.au/legal-and-justice/consumer-rights-and-protection/guarantees-contracts-and-warranties/consumer-guarantees (checked October 2026)
    2. NRMA, “What do my dashboard warning lights mean” – red warning lights need prompt action; have a technician diagnose faults. https://mynrma.com.au/cars-and-driving/car-servicing/resources/what-do-my-dashboard-warning-lights-mean (checked October 2026)
    3. NT Government, “Quotes and estimates” – a quote is a fixed price that becomes a contract once accepted; an estimate is not fixed; what a written quote should include; set a limit and ask to be contacted. https://nt.gov.au/law/rights/quotes-and-estimates (checked October 2026)

  • Have rats or mice chewed my car wiring?

    Quick answer

    Signs of rodent damage include sudden warning lights or odd electrical faults after the car has been parked, chewed insulation or loom tape, droppings, nesting material (leaves, paper, insulation) under the bonnet or in the air filter box, and a burning or unpleasant smell. Rodents shelter in warm engine bays and gnaw to wear down their teeth. Small, visible damage can sometimes be repaired, but damaged looms often need professional repair, and some insurance policies exclude rodent damage, so check your policy.

    Is this a DIY job?

    • Difficulty: Easy to inspect; Pro to repair most wiring damage
    • Time: 15 to 30 minutes to inspect
    • Tools: torch, gloves, mask, camera
    • Skills: careful looking

    Repairing wiring properly means matching wire sizes, staggering joints, sealing against moisture and protecting the loom again. Damaged looms may also carry sensors, airbag or driver-assistance circuits. Most owners leave repairs to an auto electrician.

    Step by step

    1. Don’t keep driving with new, unexplained warnings. If warning lights appear suddenly, the engine runs badly, or you smell burning, park safely and investigate before driving further.
    2. Open the bonnet and look carefully with a torch. Wear gloves and a mask: droppings and nests can carry disease.
    3. Look for the tell-tale signs: – chewed insulation, exposed copper or bitten loom tape and conduit – droppings, urine stains, food scraps, nests in corners, on top of the engine or in the air filter box – chewed insulation pads on the underside of the bonnet
    4. Check the air intake and cabin filter. Rodents often nest in air boxes and the cabin air intake below the windscreen. A blocked or chewed filter can cause smells and poor airflow.
    5. Photograph everything. Photos help with an insurance claim and a repair quote.
    6. Check your insurance policy. Some policies exclude damage by rodents or vermin. Ask your insurer before starting repairs.
    7. Get the wiring repaired. An auto electrician will trace every damaged wire, repair or replace the section, and re-protect the loom. Then any fault codes are read and cleared.
    8. Clean out nests safely. Wear gloves and a mask. Don’t sweep, vacuum or blow out dry droppings. Spray the nest and droppings with disinfectant or a diluted bleach solution, let it soak for a few minutes, then pick it up with paper towel and seal it in a bag. Wash your hands afterwards.
    9. Reduce the chance of a return visit. See the prevention list below.

    Specs table

    Prevention

    What to do Why
    Don’t leave food, pet food or rubbish in or near the car Food attracts rodents
    Keep the garage or parking area tidy and sealed Fewer hiding places and entry points
    Trim branches and vegetation near where the car parks Reduces access
    Use baits only in lockable bait stations, or traps Bait stations keep pets, children and other animals out; follow label directions
    Start and drive the car regularly A car that sits for weeks is more inviting
    Check under the bonnet if the car has been parked for a while Catch damage early
    Consider rodent-deterrent tape or mesh over air intakes Some owners use these; results vary

    Common symptoms after rodent damage

    Symptom Possible cause
    Sudden check engine or other warning lights Sensor wiring chewed
    Car won’t start or cranks but won’t start Starting, sensor or fuel pump circuit damaged
    Lights, wipers or gauges acting oddly Chewed body or lighting wiring
    Burning smell Short circuit, or nest on a hot exhaust
    Musty smell through the vents Nest or droppings in the cabin air intake

    What you’ll need

    For prevention and inspection:

    • rodent deterrent tape
    • split loom tube (to protect exposed wiring after repair)
    • cabin air filter (if contaminated)

    For repair (usually by a professional): automotive wire, solder sleeve connectors, adhesive heat shrink, loom tape.

    When to call an auto electrician

    • Any chewed wiring, especially in the engine loom, near sensors or near the airbag and driver-assistance wiring.
    • Warning lights or running problems after rodent activity.
    • Hybrid or EV high-voltage (orange) cables are damaged. Don’t touch them: professional-only.
    • There’s a burning smell, melted insulation or signs of a short circuit.

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

    Find an auto electrician near you

    Related questions

    Q: Does car insurance cover rat damage? A: It depends on the policy. Some exclude damage by rodents or vermin. Check your product disclosure statement or ask your insurer before repairs start.

    Q: Why do rats chew car wiring? A: Rodents gnaw constantly to keep their teeth worn down, and warm, sheltered engine bays are attractive in cooler weather. Food and nesting material nearby make it more likely.

    Q: How much does it cost to repair rodent damage? A: It depends on how much wiring is damaged and whether a loom must be replaced. Minor repairs can be modest; extensive damage can cost thousands of dollars or even make a car uneconomical to repair. Get a written quote after inspection.

    Q: Do ultrasonic rodent repellers work in cars? A: Results are mixed and there’s limited independent evidence. Removing food, sealing access and regular use of the car are more reliable.

    Sources

    1. The New Daily, “Rats car damage” (April 2021) – rodents seeking warmth in engine bays, gnawing on wiring; example repair cost around $2,000 and a car written off; insurance exclusion example; Brisbane City Council prevention advice; bait stations. https://thenewdaily.com.au/news/queensland/2021/04/23/rats-car-damage (checked October 2026)
    2. Brisbane City Council, “Rats and mice” – baits and traps; follow label safety instructions; lockable bait stations and traps are safer around children and pets. https://www.brisbane.qld.gov.au/environment-waste/natural-environment/biodiversity-brisbane/wildlife-brisbane/pest-animals-invasive-species/rats-mice (checked October 2026)
    3. SA Health, “Rats and mice – prevention and control” – remove food and shelter, cut back vegetation, seal entry points; rodents can carry diseases such as leptospirosis. https://www.sahealth.sa.gov.au/wps/wcm/connect/Public+Content/SA+Health+Internet/Conditions/Bites+stings+and+pests/Rats+and+mice+prevention+and+control (checked October 2026)
    4. NSW Health, “Staying healthy during a mouse plague” – diseases spread by rodent urine and droppings; wear gloves, clean with disinfectant or bleach, wash hands. https://www.health.nsw.gov.au/environment/factsheets/Pages/mouse-plague.aspx (checked October 2026)
    5. US Centers for Disease Control and Prevention, “How to clean up after rodents” – soak droppings and nests with disinfectant before removal; don’t sweep or vacuum; bag and seal. https://cdc.gov/healthy-pets/rodent-control/clean-up.html (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.

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

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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 clean corroded battery terminals?

    Quick answer

    Wear gloves and safety glasses, disconnect the negative terminal first and then the positive, and scrub the white, blue or green deposits off the posts and clamps with a battery terminal brush. A solution of bicarbonate of soda (bicarb) and water helps neutralise acid residue. Rinse with a little clean water, dry everything, reconnect positive first and negative last, then protect the terminals with a terminal spray or grease. If the corrosion keeps coming back, have the battery and charging system checked.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 15 to 30 minutes
    • Tools: battery terminal brush (or a stiff wire brush), spanner (often 10 mm), bicarb soda, water, old toothbrush, rags, gloves, safety glasses
    • Skills: basic hand tools

    Step by step

    1. Protect yourself. Wear gloves and safety glasses. The deposits contain acid residue. Take off rings and metal watch bands.
    2. Check your manual. Note any radio code or reset steps, and whether your car needs special care when the battery is disconnected. (see How do I replace a car battery?)
    3. Switch everything off. Ignition off, key out.
    4. Disconnect the negative (−) terminal first, then the positive (+). Tuck the clamps away from the posts.
    5. Mix a cleaning solution. About a tablespoon of bicarb soda in a cup of warm water is a common home mix.
    6. Scrub the clamps and posts. Dip the brush in the solution and scrub. Fizzing means the bicarb is reacting with acid residue; keep applying until the fizzing stops, which tells you the acid has been neutralised. Use the terminal brush’s post end on the battery posts and the clamp end inside the clamps. If the battery has removable vent caps, make sure they’re fitted tightly first, and don’t let solution run into the cells.
    7. Rinse and dry. Wipe with a rag dampened in clean water, then dry thoroughly. Keep runoff away from paint and wiring where you can, and rinse any splashes off the paint.
    8. Check the cables. Pull back the boot on each clamp. If the copper under the insulation is green or the cable is stiff and swollen, the corrosion has spread up the cable and the cable or clamp should be replaced.
    9. Reconnect positive (+) first, then negative (−) last. Tighten firmly, but don’t over-tighten soft lead posts.
    10. Protect the terminals. Spray with terminal protector or apply a thin coat of terminal grease.
    11. Start and check. Start the car and check for warning lights. Reset radio, clock and windows if needed.

    Why bicarb soda works

    Most terminal corrosion on a lead-acid battery comes from battery acid getting out. When a battery is overcharged or runs hot, the acid inside can boil and vent, and the acid that escapes settles on the terminals and clamps and eats into them. Bicarb soda is a mild alkali. It reacts with the acid residue and turns it into harmless salts, water and carbon dioxide (the fizz), so the residue is inert and can be wiped and rinsed away safely. Scrubbing alone moves the acid around; bicarb neutralises it.

    If the battery has boiled acid out, cleaning fixes the symptom, not the cause. Have the charging system checked, because a high charging voltage will keep boiling the battery.

    Specs table

    What the corrosion is telling you

    What you see What it usually means
    Light white or grey powder Normal minor corrosion from acid vapour; clean and protect
    Heavy build-up that keeps returning Battery venting or leaking; possible overcharging; get battery and charging tested
    Green corrosion on clamps and up the cable Copper corrosion; clean and check whether the cable or clamp needs replacing
    Wet or crusty battery case, swelling Leaking or failing battery: replace it
    Corrosion and slow cranking or flickering lights Corrosion is likely causing a poor connection

    What you’ll need

    • battery terminal brush
    • battery terminal protector spray or terminal grease
    • battery terminal clamp (if a clamp is damaged)
    • battery cable (if corrosion has spread up the cable)
    • safety glasses and nitrile gloves

    When to call an auto electrician

    • Corrosion has spread under the cable insulation, or cables are swollen or brittle.
    • Corrosion comes back quickly. The battery may be leaking, or the charging voltage may be too high. (see How do I know if my alternator needs replacing?)
    • The battery case is swollen, cracked or wet, or smells of rotten eggs.
    • Your car needs battery registration or has a battery sensor on the negative terminal that might be damaged.

    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 clean battery terminals without disconnecting them? A: It’s safer to disconnect them. A brush or spanner bridging the positive terminal to metal can cause a dangerous short. Disconnecting also lets you clean the contact surfaces properly.

    Q: Can I use Coca-Cola to clean battery terminals? A: It’s a popular trick, but it leaves sticky residue. Bicarb soda and water neutralise acid and rinse off cleanly.

    Q: What causes battery terminal corrosion? A: Battery acid escaping and reacting with the metal posts and clamps. A little acid vapour causes light corrosion; heavy corrosion usually means the battery has been overcharged or overheated and boiled acid out. A leaking case or loose terminals can make it worse.

    Q: Will corroded terminals stop my car starting? A: Yes. Corrosion adds resistance, which can cause slow cranking, clicking or no start at all. (see Is it my starter motor or my battery?)

    Sources

    1. RACV, “Car battery replacement” – battery management systems and registration on some vehicles. https://racv.com.au/on-the-road/roadside-assistance/car-battery-replacement.html (checked October 2026)
    2. Planet Ark, Recycling Near You, “Recycling lead-acid batteries” – lead-acid batteries are hazardous; disposal guidance. https://recyclingnearyou.com.au/car-batteries (checked October 2026)
    3. Rolls Battery, “Cleaning – batteries and terminals” – baking soda and water solution for cleaning, vent caps closed first, rinse with water, wire-brush terminals and re-apply protective grease. https://support.rollsbattery.com/en/support/solutions/articles/646-cleaning-batteries-terminals (checked October 2026)
    4. Technical review, Ozautoelectrics (October 2026) – bicarb soda reacts with acid residue from batteries that have boiled acid out, neutralising it so it no longer corrodes the terminals. Consistent with standard acid–base chemistry (sodium bicarbonate + sulphuric acid → sodium sulphate, water and carbon dioxide).

  • How do I choose an auto electrician?

    Quick answer

    Look for a qualified auto electrician who does the type of work you need, holds any licence your state or the job requires (for example an ARC refrigerant licence for air conditioning), gives a clear written quote, and explains the warranty on parts and labour. Ask a few direct questions before you book and compare like with like. This site doesn’t recommend particular businesses: use the checklist below to decide for yourself.

    Is this a DIY job?

    • Difficulty: Not applicable (this is a buying guide)
    • Time: 15 to 30 minutes to make a few calls
    • Tools: the checklist below, your vehicle details, notes and photos of the problem
    • Skills: none

    Step by step

    1. Work out what kind of job it is. A no-start, a flat battery, an electrical fault, an accessory install (dual battery, brake controller, lights), or air conditioning. Some auto electricians focus on diagnosis and repairs, others on 4WD and caravan fit-outs, trucks, or air conditioning. Ask whether they regularly do your type of job and your type of vehicle.
    2. Check qualifications. The trade qualification is the Certificate III in Automotive Electrical Technology. Ask whether the person working on your car is qualified, or is an apprentice working under supervision. Both are fine; you just want to know.
    3. Check licences that apply. – Air conditioning: anyone handling refrigerant must hold a refrigerant handling licence from the Australian Refrigeration Council (ARC). You can check a technician’s licence through the ARC website. – State repairer licensing: some states license motor vehicle repair businesses. For example, NSW requires a motor vehicle repairer licence, and WA requires repair businesses to be licensed and repairers (including auto electricians) to be certified. Rules differ between states, so check with your state’s fair trading or consumer protection office. – 240V wiring: fixed 240V wiring in a caravan, camper or vehicle is licensed electrical work. Ask whether a licensed electrician will do that part.
    4. Ask about equipment. For modern cars, ask whether they have diagnostic equipment for your make, and whether they can do battery registration, programming or calibration if the job needs it.
    5. Ask how they charge. Fixed price, hourly, or a diagnostic fee first? Is there a call-out fee for mobile work? Does the quote include GST? (see How much do auto electricians charge in Australia?)
    6. Ask about parts and warranty. New, reconditioned or genuine parts? How long is the warranty on parts, and on labour? What happens if the fault comes back?
    7. Get it in writing. Ask for a written quote or estimate, and ask them to call you before doing any extra work.
    8. Compare fairly. The cheapest quote isn’t always the cheapest job. Check that quotes cover the same parts, the same scope and the same warranty.
    9. Check what others say. Online reviews can help, but read the detail, not just the star rating. Look for how a business responded to problems.
    10. Keep the paperwork. Keep the quote, invoice and warranty details. If there’s a problem later, you’ll need them.

    Questions to ask before you book

    Ask Why it matters
    Do you regularly work on my type of vehicle and this type of job? Experience shortens diagnosis time
    Who will do the work, and are they qualified? Qualified tradespeople or supervised apprentices
    Do you hold an ARC refrigerant licence? (A/C jobs only) Required by law for refrigerant work
    Is the business licensed? (where your state requires it) Some states license repairers
    How do you charge for diagnosis? Avoids surprises before the repair starts
    Is there a call-out fee? Does the price include GST? Lets you compare quotes fairly
    What parts will you use, and what’s the warranty? Parts quality and cover vary
    Will you contact me before any extra work? Keeps you in control of the cost

    Your rights

    Under the Australian Consumer Law, services must be provided with acceptable care and skill, be fit for any purpose you made clear, and be delivered within a reasonable time if no date was agreed. These guarantees apply whoever you choose.

    If you have a new car under warranty, you generally don’t have to use the dealer for every job 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.

    What you’ll need

    Nothing to buy. Have these ready when you call:

    • make, model, year and VIN
    • a clear description of the problem and when it happens
    • photos of warning lights or damage

    When to call an auto electrician

    • Electrical faults you can’t trace with simple checks, warning lights that won’t clear, or a car that won’t start.
    • Accessory installs that draw high current or affect safety: dual batteries, inverters, brake controllers, winches.
    • Anything involving airbags/SRS, hybrid or EV high-voltage systems, or air conditioning refrigerant. These are professional-only.

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

    Find an auto electrician near you

    Related questions

    Q: Do I need an auto electrician or a mechanic? A: Auto electricians specialise in electrical systems: starting, charging, wiring, electronics and accessories. Mechanics focus on engines, brakes and suspension. Many faults overlap, and many workshops do both.

    Q: Is a mobile auto electrician as good as a workshop? A: Both can be. Mobile services are convenient for batteries, no-starts and many installs. A workshop may suit complex faults that need a hoist or more equipment.

    Q: How do I check an air conditioning technician’s licence? A: The Australian Refrigeration Council website has a consumer check for licence holders and authorised businesses. Ask for the licence number and check it.

    Q: What if the problem comes back after the repair? A: Contact the business promptly with your invoice. Under the Australian Consumer Law, services must be done with acceptable care and skill. If you can’t resolve it, your state’s fair trading or consumer affairs office can help.

    Sources

    1. training.gov.au, “AUR30320 Certificate III in Automotive Electrical Technology” (release 5) – qualification for servicing, diagnosing and repairing vehicle electrical systems. https://training.gov.au/assets/AUR/AUR30320_R5.pdf (checked October 2026)
    2. Australian Refrigeration Council, “Fact sheet 4: automotive air conditioning” – a refrigerant handling licence is needed to work on vehicle air conditioning; handling refrigerant without one is an offence. https://www.arctick.org/media/17421/arc5919_factsheet04_web.pdf (checked October 2026)
    3. Australian Business Licence and Information Service, “Motor Vehicle Repairer’s Licence – New South Wales”. https://ablis.business.gov.au/service/nsw/motor-vehicle-repairers-licence/16723 (checked October 2026)
    4. WA Consumer Protection, “Motor vehicle repairers licensing FAQ” – businesses licensed; repairers certified, including auto electricians. https://consumerprotection.wa.gov.au/publications/motor-vehicle-repairers-licensing-faq (checked October 2026)
    5. NSW Government, “Consumer guarantees” – guarantees for services under the Australian Consumer Law. https://www.nsw.gov.au/legal-and-justice/consumer-rights-and-protection/guarantees-contracts-and-warranties/consumer-guarantees (checked October 2026)
    6. 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)
    7. HVACR News, “ARC reports surge in online licence checks” – consumers use ARC’s online licence checks and business directory. https://hvacrnews.com.au/regulations/arc-reports-surge-in-online-licence-checks (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.

    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 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 should I do if I smell burning plastic or see smoke from my car’s wiring?

    Quick answer

    Pull over somewhere safe, switch off the ignition, put it in Park with the handbrake on, and get everyone out and well away from the car. If you see flames, or the smoke keeps coming, call Triple Zero (000) and don’t lift the bonnet. Don’t drive the car again, or reconnect anything, until an auto electrician has found and fixed the cause.

    Is this a DIY job?

    • Difficulty: Pro only
    • Time: Your part takes minutes: get safe, then arrange a tow
    • Tools: phone; a vehicle fire extinguisher only if you already carry one and feel confident using it
    • Skills: none: this is about staying safe, not repairing

    A burning plastic smell or smoke from wiring means something is overheating: a short circuit, a failed component, a loose high-current connection, or wiring that has rubbed through or been chewed. Any of these can start a fire. Finding the cause takes the right test equipment and wiring information, so leave the diagnosis and repair to a professional. This article covers only what you should do.

    Step by step: what to do right now

    1. Pull over safely. Indicate, get off the road as soon as it’s safe and stop away from dry grass, buildings, fuel bowsers and other cars.
    2. Ignition off. Turn the engine off, put the car in Park (or in gear for a manual) and apply the handbrake.
    3. Get everyone out. Get all passengers out, including children and pets, and move well away from the car, to the side away from traffic. Take your phone. Leave belongings behind.
    4. Don’t breathe the smoke. Burning plastic gives off toxic fumes. Stay upwind if you can.
    5. Call 000 if there’s fire. If you see flames, or the smoke is increasing, call Triple Zero (000) and ask for the fire service. Tell them where you are and, if relevant, that the car is a hybrid, EV or runs on LPG.
    6. Don’t lift the bonnet if there are flames. Opening the bonnet lets in a rush of air that can make a fire flare up and cause serious burns.
    7. Use an extinguisher only if it’s safe. Only if you carry one and feel confident. Fire Rescue Victoria’s advice for a fire under the bonnet is to release the bonnet catch but not lift the bonnet, and aim the extinguisher through the gap. For a fire in the cabin, aim it at the fire and then close the door. If in doubt, stay back and wait for firefighters.
    8. LPG cars: turn off the gas at the main valve, but only if you know where it is and can reach it safely.
    9. If there are no flames and the smoke has stopped, stay away from the car for a while and watch it from a safe distance. Wiring can keep smouldering after you switch off.
    10. Disconnect the battery only if it’s safe. Only once there are no flames, the smoke has stopped and nothing is hot to touch. Remove the negative terminal first, then the positive, and tuck both leads away from the posts. Don’t do this on a hybrid or EV: their high-voltage systems are professional only. If you’re not sure, leave it.
    11. Don’t restart or reconnect. Don’t start the car “to see if it happens again” and don’t reconnect the battery. The fault is still there.
    12. Arrange a tow. Have the car taken to an auto electrician or workshop rather than driving it.
    13. Tell your insurer if there was any fire damage.
    14. Check for recalls. Some vehicles have been recalled because of wiring or component fire risks. You can search by make and model on the Australian Government’s vehicle recalls website (see Sources).

    Hybrids and electric vehicles

    Hybrids and EVs have high-voltage batteries and wiring (usually in orange covering) as well as the normal 12V system. Never touch high-voltage parts, cut cables or disconnect anything on these cars after smoke or a fire. Fire Rescue Victoria warns that a damaged EV battery can catch fire hours, days or even weeks after the event, and advises keeping a damaged EV in the open, at least 15 metres from other vehicles, buildings and anything that can burn. If the battery itself is smoking or burning, call 000 and wait somewhere safe.

    Specs table

    What to do in each situation

    What you notice What to do
    Flames anywhere Get everyone out and away, call 000, don’t lift the bonnet
    Smoke from under the bonnet or dash, no flames Pull over, ignition off, everyone out, call 000 if it keeps coming or gets worse
    Burning plastic smell, no smoke Pull over, ignition off, get out and check from outside; don’t keep driving
    Smell comes back each time you use one accessory Stop using it, pull the accessory’s fuse if you can reach it safely, book an inspection
    Rotten egg smell near the battery Battery may be overcharging or failing; keep away from sparks and flames
    Smoke or smell on a hybrid or EV Everyone out and away; call 000 if smoking or burning; don’t touch high-voltage parts

    Fire extinguisher for a vehicle

    Item Fire Rescue Victoria advice
    Type Dry powder portable extinguisher rated 1A 5B(E)
    Where Somewhere easily reached in the vehicle

    What you’ll need

    This isn’t a DIY repair, so there are no parts to buy for the fix. To be prepared:

    • vehicle fire extinguisher dry powder with a mounting bracket
    • battery isolator switch: turning it off cuts the battery off from the whole vehicle in seconds, without spanners. It also stops small background current draws from flattening the battery while the vehicle is parked for long periods, which makes it popular on 4WDs, caravans, boats and vehicles that sit unused. Have an auto electrician fit it, because it carries the full starter current.

    Commercial and mining vehicles. Some vehicles must carry an extinguisher by law or by site rules:

    • Vehicles carrying a placard load of dangerous goods must carry fire extinguishers under the Australian Dangerous Goods Code (chapter 12). The number and size depend on the load, from one 2 kg dry chemical powder extinguisher for packaged goods up to larger units in the load area for bulk flammable goods.
    • Mine sites set their own requirements for light vehicles and mobile plant, and commonly require an extinguisher in every vehicle. Check the site’s rules before you go on site.

    Browse vehicle fire extinguishers on Ozautoelectrics.

    When to call an auto electrician

    Always, after any burning smell or smoke from wiring. In particular:

    • You’ve had smoke, melted wiring or a blown fuse that keeps blowing.
    • The smell started after an accessory was fitted (driving lights, a dashcam, a dual battery, a stereo or a towbar harness).
    • You’ve found signs of rodent damage under the bonnet. (see Have rats or mice chewed my car wiring?)
    • The car has been in a flood or had water inside.
    • The car is a hybrid or EV. High-voltage systems are professional only.
    • Airbag/SRS wiring is involved (under the seats, in the steering wheel or dash). Airbag work is professional only.

    Ask for the car to be towed rather than driven. Fire Rescue Victoria advises not driving a car after a fire until an auto electrician or qualified mechanic has checked it.

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

    Find an auto electrician near you

    Related questions

    Q: Is it safe to drive with a burning plastic smell? A: No. Pull over, switch off and get out. A burning plastic smell usually means something electrical is overheating, and wiring can catch fire with little warning.

    Q: Should I disconnect the battery after smoke from wiring? A: Only if there are no flames, the smoke has stopped and you can do it safely. Remove the negative terminal first. Never disconnect anything on a hybrid or EV’s high-voltage system.

    Q: Why shouldn’t I open the bonnet if there’s a fire? A: Lifting the bonnet lets a rush of air reach the fire, which can make it flare up and cause serious burns. Call 000 and stay back.

    Q: What causes car wiring to burn? A: Common causes include short circuits, poor connections that heat up under load, wiring rubbed through on metal edges, rodent damage, water damage, and accessories wired with cable that’s too thin or not fused properly. (see What size cable do I need for my 12V accessory?)

    Q: Can I just replace the melted wire myself? A: It isn’t recommended. The melted wire is usually a symptom, not the cause. Unless the original fault is found, it can happen again.

    Sources

    1. Fire Rescue Victoria, “Vehicles and boats” – what to do if a vehicle catches fire: ignition off, Park and handbrake, get out, call 000; release the bonnet catch only and don’t lift the bonnet; toxic smoke from burning plastics; remove battery leads after the fire is out if safe; don’t drive until checked by an auto electrician or qualified mechanic; 1A 5B(E) dry powder extinguisher; damaged EV batteries may ignite hours, days or weeks later; keep damaged EVs at least 15 m from other vehicles and buildings. https://frv.vic.gov.au/vehicles-and-boats (checked October 2026)
    2. Australian Government, Vehicle Recalls (Department of Infrastructure, Transport, Regional Development, Communications and the Arts listed as regulator) – searchable vehicle recalls, including wiring and component fire risks. https://www.vehiclerecalls.gov.au/ (checked October 2026)
    3. National Transport Commission, “Australian Dangerous Goods Code Review – Discussion Paper 5: Fire Extinguishers” – ADG Code chapter 12 (12.1.2, Table 12.1): fire extinguisher requirements for road vehicles carrying placard loads. https://www.ntc.gov.au/sites/default/files/assets/files/Australian%20Dangerous%20Goods%20Code%20Review%20-%20Discussion%20Paper%205%20-%20Fire%20Extinguishers.pdf (checked October 2026)

  • 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.

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

    Find an auto electrician near you

    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)

  • Why aren’t my trailer lights working?

    Quick answer

    Most trailer light faults come down to four things: a poor earth, corroded plug or socket pins, a blown globe, or a blown fuse or faulty module on the vehicle side. Start by testing the vehicle’s socket with a trailer tester. If the socket works, the fault is on the trailer, and the earth is the first thing to check. Lights that glow dimly, flash together or work the “wrong way” almost always point to a bad earth.

    Is this a DIY job?

    • Difficulty: Easy
    • Time: 15 to 60 minutes
    • Tools: trailer circuit tester (or a helper), multimeter or test light, wire brush, contact cleaner, screwdriver, spare globes
    • Skills: basic electrical checks

    Step by step

    1. Test the vehicle side first. Plug a trailer circuit tester into the vehicle’s socket, or use a test light between each pin and pin 3 (earth). Check tail lights, left and right indicators, stop lights and reversing lights. This tells you which half has the fault.
    2. If the vehicle socket fails: – Check the towbar or trailer fuses (many vehicles have dedicated ones; see the owner’s manual or the towbar harness instructions). – Look inside the socket for green corrosion or bent pins. Clean with contact cleaner and a small brush. – Many modern vehicles feed the socket through a trailer module. If the module has no power or has been damaged, the socket won’t work. (see Do I need a vehicle-specific towbar wiring harness?)
    3. If the vehicle socket works, check the trailer plug. Open it and check every wire is tight and there’s no corrosion. Cut back and re-terminate any wire that’s green or brittle. (see How do I wire a 7-pin flat or 7-pin round trailer plug?)
    4. Check the trailer earth. Follow the white earth wire from the plug to where it bolts to the trailer chassis. Remove the bolt, clean the terminal and the chassis back to bare metal, refit and protect it. Many trailers also rely on each lamp’s mounting for earth: check those too.
    5. Check the globes. Swap in new globes or test them. A blackened or broken filament means it’s blown. LED lamps can’t usually be repaired; replace the lamp.
    6. Check the lamp sockets. Corrosion in a lamp holder causes flickering. Clean it, and use a little dielectric grease to keep moisture out.
    7. Look for damaged cable. Check the cable along the drawbar and under the trailer for cuts, crushing or rubbing, especially where it passes through holes without grommets.
    8. Retest everything before you tow, including brakes if fitted.

    Specs table

    Symptom and likely cause

    Symptom Likely cause
    Nothing works Vehicle fuse or trailer module, plug not fully in, broken earth
    Lights dim, or glow when other lights are on Poor earth (most common)
    Indicator lights up the tail lights, or both sides flash Poor earth
    One function missing on both sides That pin or wire at the plug or socket
    One lamp out Globe, lamp socket, or that lamp’s earth
    Works when wiggling the plug Corroded pins or loose wire in plug or socket
    Indicators flash fast with trailer on Trailer globe out, or LED trailer lamps on an older flasher
    Trailer lights fine, brakes weak Earth, pin 5 connection, or brake controller setting

    Pin reference (7-pin flat and 7-pin large round): 1 left indicator (yellow), 2 reversing (black), 3 earth (white), 4 right indicator (green), 5 electric brakes (blue), 6 stop (red), 7 tail (brown).

    What you’ll need

    • trailer circuit tester
    • 12V test light
    • electrical contact cleaner
    • dielectric grease
    • ring terminals and adhesive heat shrink
    • LED trailer lamps or trailer globes
    • 7 pin flat trailer plug (if the plug is badly corroded)

    When to call an auto electrician

    • The vehicle socket doesn’t work and the fuses are fine.
    • The trailer module or towbar harness has failed, or the vehicle shows trailer or lamp warnings.
    • The trailer cable needs replacing along its length, or the trailer has electric brakes that aren’t working properly.
    • You can’t find the fault after checking the earth and plug.

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    Related questions

    Q: Why do my trailer lights flicker? A: Usually a poor earth or corroded pins. Clean the earth point back to bare metal and clean the plug and socket.

    Q: Why does my car’s indicator flash fast with the trailer connected? A: A trailer indicator globe is likely blown. If the trailer has LED lamps and the vehicle is older, the flasher may not recognise the low load.

    Q: Can I use the towball for the trailer earth? A: No. The towball and coupling aren’t a reliable electrical path, and the trailer rules require a dedicated earth return wire between the trailer and the vehicle. Use the white earth wire through the plug.

    Q: Do LED trailer lights need special wiring? A: Usually not, but they’re sensitive to poor earths, and some vehicles need a trailer module to recognise them.

    Sources

    1. ExplorOz, “Trailer wiring diagrams” – pin functions and colours. https://www.exploroz.com/vehicle/electrics/trailerwiringdiagrams.aspx (checked October 2026)
    2. Department of Infrastructure, Vehicle Standards Bulletin 1 (Revision 6, August 2026) – trailers up to 3,500 kg ATM use a 7-pin or 12-pin plug to AS 4177.5; 7-pin functions and colours; an earth return wire between trailer and tow vehicle must be provided; required trailer lamps. https://www.infrastructure.gov.au/sites/default/files/documents/vsb1-revision-6-trailers-with-an-aggregate-trailer-mass-of-4.5-tonnes-or-less-august-2026.pdf (checked October 2026)