MotR
Most Common MOT Failure · Lighting

Lighting MOT Failures

Lighting and signalling faults are the single most common MOT failure category — accounting for roughly one in five of all failures. They are also the easiest to prevent. A 10-minute check of every lamp costs nothing and eliminates the most avoidable failure type.

Official UK dataFree to useInstant resultsNo account needed
Lighting MOT Failures

Quick Answer

Lighting faults account for approximately 18–20% of all UK MOT failures — the largest single category every year. Most lighting failures cost under £25 and take 10 minutes to fix at home. A systematic check of all lights the week before your MOT appointment eliminates the most common and easily avoidable failure type.
The full checklist

Every Light the MOT Tests — and What Can Fail

Light / SystemWhat is testedTypical failure reasonTypical cost to fix
Headlamps — dipped beamOperation, aim, beam patternBlown bulb, moisture in unit, aim misaligned£5–£150
Headlamps — main beamOperation on both sidesBlown bulb (separate filament from dipped)£5–£80
Front direction indicatorsOperation, correct flash rate (60–120 per minute)Blown bulb, faulty relay causing wrong flash rate£5–£50
Rear direction indicatorsOperation, correct flash rateBlown bulb, corroded bulb holder£5–£30
Side repeater indicatorsOperationBlown bulb, broken lens£5–£20
Brake lightsOperation — one, two, or three lights per carBlown bulb, faulty brake light switch£5–£60
Rear number plate lightsMust illuminate the plateBlown bulb — often forgotten entirely£3–£20
Rear fog lightOne or two rear fogs — must operate correctlyBlown bulb, blown fuse£5–£30
Reversing lightsOperation, though advisory only if not OEMBlown bulb, faulty reverse switch£5–£30
Hazard warning lightsAll four indicators must flash simultaneouslyRelay fault or individual bulb failure£5–£60

Cost estimates are for bulb or minor component replacement at an independent garage or self-fitted, 2026. Xenon/LED sealed units significantly higher.

Do this the week before

The 10-Minute Pre-MOT Lighting Check

Do this the week before your MOT appointment so you have time to buy any replacement bulbs. Park against a light-coloured wall or closed garage door after dark. Work through each lighting function systematically.

Dipped headlamps — both sides illuminate, beam pattern correct, no moisture fogging the lens
Main beam — both sides switch on, no warning light remaining on when switched to dipped
Left and right front indicators — correct flash rate, steady flash without flickering
Left and right rear indicators — correct flash rate, no dim or intermittent operation
Side repeater indicators — usually on the door mirrors or front wings
Brake lights — have a helper watch, or use reversing camera or wall reflection while pressing pedal
Number plate illumination — easily overlooked, often fails on older vehicles
Rear fog light — press button and check one (or both) rear fogs illuminate
Hazard warning lights — all four indicators should flash simultaneously, same rate
Headlamp aim — if recently replaced a headlamp, confirm aim has not shifted
Related guides

Related MOT Failure Guides

MOT Failures Hub

Complete guide to all failure categories

Open

Common MOT Failures

Statistics and overview

Open

Brake MOT Failures

Most safety-critical failures

Open

Windscreen MOT Failures

Chips, cracks, zones

Open

MOT Failure Costs UK

Cost guide for all categories

Open

MOT Status Check

Is your current MOT valid?

Open

MOT Checklist

Full pre-test preparation guide

Open

MOT Guide

Complete MOT reference

Open
Questions & answers

Frequently Asked Questions

What lighting problems cause an MOT failure?
Any light required by law that does not function correctly will cause a failure. This includes: headlamps not operating on main or dipped beam, direction indicators not flashing at the correct rate or not working at all, brake lights not illuminating when the pedal is pressed, rear fog lights not working, and hazard warning lights not operating. The number plate illumination lamp is also checked.
How do I check my lights before an MOT?
Park in front of a reflective surface (garage door or wall) at night or in a dark area. Turn on headlamps, main beam, and all individual functions. Check brake lights with a helper or reversing camera reflection. Check indicators — front, rear, and side repeaters. Check number plate illumination, fog lights, and reversing lights. The whole check takes under 10 minutes and costs nothing.
Can I replace bulbs myself before an MOT?
Yes — most standard halogen bulbs can be replaced at home. Many modern vehicles make individual bulb replacement difficult due to tight engine bay packaging, but it is generally possible with some patience. LED and Xenon headlamp failures often require garage attention. Always check the correct bulb specification before purchasing.
What is headlamp aim failure?
Headlamp aim must be correctly adjusted so that dipped beams illuminate the road ahead without blinding oncoming drivers. Aim is checked using calibrated optical equipment. Headlamps pointing too high will fail; those pointing too low will result in an advisory. Most test centres can adjust aim during the test for a small charge.
Do DRL (daytime running lights) fail the MOT?
Daytime running lights are checked if they are standard factory-fitted equipment. If a DRL is not functioning, it may cause a failure on vehicles where DRLs are a legal requirement on the specific model. Aftermarket DRL additions are generally not tested unless they interfere with other lighting.
How much does it cost to fix lighting failures?
Standard halogen bulb: £5–£25 for the bulb, or free if you fit it yourself. Xenon/HID headlamp bulb (garage-fitted): £50–£150 per bulb. LED headlamp unit replacement (if the unit is sealed): £150–£400 per side. Indicator relay replacement: £20–£60. Wiring or switch repair (intermittent fault): £50–£200 depending on complexity.
Check before your test

Free MOT Tools

MOT Status Check

Is your current MOT valid?

Open

MOT History Checker

Every test, advisory, failure and mileage reading

Open

MOT Due Date Check

Exactly when is your MOT due?

Open

MOT Risk Checker

Predict your failure risk before the test

Open
SR

Ste Robinson

Founder, MotR · Last reviewed 12 June 2026

Ste Robinson is the founder of MotR, helping UK drivers check MOT history, tax status, vehicle records and ownership information using official DVLA and DVSA data.

Check Your MOT Status Before You Test

MOT status, history, and advisories — free official DVSA data in 30 seconds.

Lighting MOT standards sourced from the DVSA MOT Inspection Manual. Repair costs are UK independent garage / self-fit estimates, 2026. Xenon/LED sealed units significantly higher.

Keep reading

Windscreen MOT Failures

Zones, chip size limits, replacement costs — exactly what the MOT checks on your windscreen.

Open