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
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
- 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.
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
- 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)
- 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)
- 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)