A light bulb symbol with an exclamation mark means an exterior lamp has failed. How to find which bulb, the law and the MOT.
Looking for more detail? Our full guide covers this topic in depth, with step-by-step advice and sources.
One of the exterior lights, such as a brake light, indicator or headlight, has failed or has a wiring fault.
What it looks like
A light bulb with an exclamation mark, or a lamp symbol. Colour: Amber.
Common causes
- Blown bulb
- Corroded bulb holder or connector
- Wrong bulb type fitted
What to do
- Walk round the car with lights, indicators and brakes on (ask someone to press the brake, or use a reflection).
- Replace the bulb with the correct type from the handbook. Many LED units need a garage.
- Drivers must keep lights working; police can stop you for defective lights.
Can I keep driving?
Yes, but fix it quickly, especially brake lights and headlights.
MOT
Lamps that do not work are an MOT fail.
Symbols vary slightly between makes. Always check your owner's handbook. General guidance only; if in doubt, call your breakdown provider.
Sources and further reading
Facts checked on 20 October 2026. Spotted an error? Tell us and we will correct it.