Interior LED bulbs in the Audi A3 are a size-code exercise first and a CANbus exercise second. Get the bulb code right (194, T10, festoon 31 or 36 or 42 mm, W5W or C5W), then decide whether CANbus-decoded bulbs are worth the small extra outlay given that this car is known to be CANbus-sensitive.
Fit facts at a glance
| Detail | UK-market note |
|---|---|
| Common interior bulb codes | 194 and T10 (wedge), festoon 31/36/42 mm, W5W (wedge equivalent), C5W (festoon equivalent) |
| CANbus sensitivity | known to be CANbus-sensitive |
| Colour temperature for reading/map | 4000-5000K neutral white is the sweet spot |
| Colour temperature for bright cabin | 6000K daylight-white is brighter but harsher |
| Rated bulb life | 25,000-50,000 hours (versus around 1,000 hours for incandescent) |
| Regulation for on-road use | Interior LED replacement in existing sockets is not regulated the way exterior lighting is |
What to look for on the listing
- That the bulb size code (194, T10, festoon length in mm) matches the actual sockets in your car, not just a similar-looking picture.
- Whether the kit lists ‘CANbus-ready’ or ‘CANbus-decoded’, which is worth having on the Audi A3 because this car is known to be CANbus-sensitive.
- Colour temperature in kelvin: 4000-5000K is easier on the eyes for reading than 6000K.
- Whether the kit covers dome, map, vanity, boot and glovebox rather than only two of the five.
Frequently asked questions
Are these bulbs CANbus-sensitive on the Audi A3?
This car is known to be CANbus-sensitive. This brand’s cars are among the more CANbus-sensitive in the UK market, so pick bulbs explicitly labelled CANbus-ready or plan on an inline resistor to avoid a bulb-out warning on the dash.
What colour temperature works best inside a car?
Around 4000-5000K neutral white is the sweet spot for reading a map or a phone screen without eye fatigue. 6000K daylight-white is brighter but harsher; 3000K warm-white can be too dim on cheap bulbs.