Motor Vehicle Expert
MOT lighting guide

Car Fails MOT on Lights

If your car fails its MOT on lights, the problem is often a blown bulb, poor beam alignment, cracked lens or faulty wiring. Many lighting failures are straightforward to fix.

Quick answer Common reasons

Quick answer

Lighting faults are one of the most common MOT failures. Often the fix is simple, but damaged units or electrical issues can cost more.

Checking every exterior light before the test can save time and money.

Common reasons a car fails MOT on lights

Blown bulbs

A very common fail reason.

Headlight aim

Beam too high or low.

Cracked lens

Damage affecting output or safety.

Wrong colour

Incorrect bulb or damaged lens.

Water ingress

Condensation or corrosion inside unit.

Electrical fault

Fuse, switch or wiring issue.

Likely UK repair costs

  • 1Bulb replacement: often low cost
  • 2Headlight alignment: modest cost
  • 3Lens/unit replacement: moderate to higher cost
  • 4LED module faults: can be higher
  • 5Wiring diagnosis: varies by labour time

Quick checks before MOT

Check headlights, brake lights, indicators, reverse lights, number plate lights and fog lights. Ask someone to help with brake lights if needed.

Replace failed bulbs before attending the test.