Which Lights Fail an MOT? Reverse Lights, DRLs, Fog Lights and More

Almost any lamp the law requires will fail an MOT if it does not work: headlamps, side lights (position lamps), stop lamps, indicators, hazard lights, the rear fog lamp, the number plate lamp and the rear reflectors. A failed lamp is usually a major defect, which is an MOT fail, and having no working stop lamps at all is a dangerous defect. Some lamps are only tested on newer vehicles: reversing lamps on vehicles first used from 1 September 2009, and daytime running lamps and front fog lamps on cars first used from 1 March 2018. Agricultural tractors do not need an MOT at all, but their lights still have to work by law.

This guide goes lamp by lamp through what the MOT tester checks, which vehicles each check applies to, and what counts as a minor, major or dangerous defect. It is based on the DVSA MOT inspection manual for cars and light commercial vehicles (section 4, lamps, reflectors and electrical equipment).

MOT lighting checks at a glance

Lamp	Which vehicles	Not working
Headlamps (dipped and main beam)	All, except very early vehicles	Major (fail)
Headlamp aim	All with headlamps	Major if out of limits
Front and rear position lamps (side lights)	All	Major (fail)
Stop lamps	All (two needed from 1 January 1971)	Major for one; dangerous if none work
Indicators and side repeaters	All (side repeaters from 1 April 1986)	Major (fail)
Hazard warning lamps	First used from 1 April 1986	Major (fail)
Rear fog lamp	First used from 1 April 1980	Major (fail)
Reversing lamps	First used from 1 September 2009	Major (fail)
Rear number plate lamp	All with position lamps	Major if none work; minor if one of two
Rear reflectors	All	Major if missing or more than half damaged
Daytime running lamps	Cars first used from 1 March 2018, if fitted as standard	As position lamps
Front fog lamps	First used from 1 March 2018	Major (fail)
13-pin trailer socket	Vehicles with a tow bar	Major if faulty; dangerous if dead

A minor defect is recorded but the vehicle still passes. A major defect is a fail and must be repaired. A dangerous defect is a fail and the vehicle should not be driven until it is fixed.

Headlamps

The tester checks that both dipped beams and both main beams light straight away, that they are a matched pair (same colour, size, shape and intensity), that the lens and reflector are not badly damaged, that the lamp is secure and that the beam is aimed within the limits. A headlamp that does not work, an aim that is out, a faulty dip switch or a seriously cracked lens are all major defects. Headlamps must be white or yellow; a bulb or tint that turns the light blue or any other colour is a fail.

LED bulbs in halogen headlamps. On vehicles first used from 1 April 1986, a halogen headlamp converted to HID or fitted with an unapproved LED bulb fails as “light source and lamp not compatible”. An LED replacement bulb (called an LEDr) is only accepted when it is approved for that exact lamp and the manufacturer’s approval sticker, with a hologram, the LEDr category, voltage and approval number, is fixed where the tester can see it. Many plug-in LED headlight bulbs sold online are marked for off-road use only and will fail. A complete replacement headlamp unit built with LED or HID light sources is fine, provided it meets the other rules. Our guide to LED headlamp conversions explains the options.

If your headlamps are dim, yellowed or flickering, see lights flickering or dim for the usual electrical causes.

Side lights (position lamps)

Two white front position lamps and two red rear position lamps are needed, lit together from one switch with the number plate lamp. A position lamp that does not work is a major defect, and so is a red light showing to the front or a white light showing to the rear. On LED lamps made up of several light sources, up to half of them out is a minor defect and more than half out is a major. See position lamps explained and position lamp not working.

Stop lamps (brake lights)

Vehicles first used from 1 January 1971 need two stop lamps, one each side, and older vehicles need at least one. They must be steady red, come on as soon as the brake is pressed and go off when it is released. One stop lamp out is a major defect. All stop lamps out, or a stop lamp that stays on after the brake is released, is a dangerous defect. A stuck-on stop lamp is usually the brake light switch rather than the lamp. Our guide to brake light bulbs lists the common bulb types.

Indicators and hazard lights

Indicators must be amber and flash between 60 and 120 times a minute. Vehicles first used from 1 April 1986 also need a side repeater on each side and working hazard warning lamps. A missing or dead indicator is a major defect, and so is a missing or dead hazard switch where hazards are required. A flash rate outside 60 to 120 a minute is a minor defect. The usual cause of a fast flash is a blown bulb on that side, or LED indicators fitted to a circuit built for bulbs; an LED-compatible flasher unit cures it. A dead indicator tell-tale on the dashboard is a minor defect.

Rear fog lamp

Vehicles first used from 1 April 1980 need at least one red rear fog lamp, fitted in the centre or on the offside, with a working tell-tale on the dashboard. If the rear fog lamp is missing or does not work, or the tell-tale for it is missing or dead, it is a major defect. See rear fog lights and the fog light symbol.

Is a reverse light an MOT failure?

Yes, on vehicles first used on or after 1 September 2009. These need at least one white reversing lamp that comes on automatically when reverse is selected, and if it does not work it is a major defect, so the vehicle fails. On some vehicles the engine must be running for the reversing lamps to come on, so the tester will check with the engine on.

Do both reverse lights need to work? The rule is that at least one reversing lamp must be fitted. The reason for rejection in the MOT manual is simply “reversing lamp inoperative”, so a second lamp that has stopped working can still be recorded against the vehicle. It is a cheap bulb, so fix it before the test rather than gamble. Vehicles first used before 1 September 2009 do not have their reversing lamps tested at all. For the common faults, see reverse lights not working and our full guide to reverse lights.

Number plate lamp and reflectors

The rear number plate lamp must light with the position lamps. If the only plate lamp, or all of them, do not work, it is a major defect; if one of two is out, it is a minor defect. A plate lamp throwing white light straight out of the back is a minor defect. Two red rear reflectors are required and reflective tape does not count as a substitute. A missing reflector, or one more than half damaged, is a major defect. See number plate lights and reflector law.

Are daytime running lights an MOT failure?

Only on cars (M1 vehicles) first used on or after 1 March 2018, and only where the daytime running lamps were fitted as standard. On those cars, the DRLs must be white, no more than two, and switch on and off with the engine, and a dead DRL is judged in the same way as a position lamp, so it is normally a fail. A DRL that switches off on the side where the indicator is flashing is normal. On older vehicles, or aftermarket DRL kits, the DRLs are not tested, but they must still be white and not dazzling. Our guide to daytime running lights and UK law covers the rules, including coloured DRLs.

Front fog lamps

Front fog lamps are only checked on vehicles first used from 1 March 2018. They must be white, work from their switch and not be badly damaged. On older vehicles they are not tested, and front fog lamps that are not wired up and have no switch do not need to work. See when to use fog lights.

Tow bar electrics

If a tow bar is fitted, the tester checks the trailer socket with a test device. A 13-pin socket that does not work properly is a major defect, and one that does not work at all is a dangerous defect. Damaged wiring to the socket is a minor or major defect depending on how bad it is. See 13-pin trailer plug wiring.

Do tractors and farm trailers need an MOT?

No. Tractors are on the government’s list of vehicles that do not need an MOT. Tractors used only for agriculture, horticulture or forestry are also exempt from goods vehicle roadworthiness testing. Tractors used for other work, such as haulage more than 15 miles from base, or tractors built to go faster than 40 km/h, can fall under goods vehicle testing instead, so check with the DVSA if that applies to you.

No MOT does not mean no rules. Every tractor and trailer on the road must have its obligatory lamps working under the Road Vehicles Lighting Regulations 1989, and the police can stop a tractor with a lamp out. Our guides to tractor lighting regulations and tractor lighting offences set out what is required. The farm pickups, vans and 4x4s that do need an MOT are tested to everything above.

Pre-MOT lighting check

1. Switch on the side lights and walk round: two white at the front, two red at the back, and the number plate lamp lit.
2. Dipped beam, then main beam, then back to dipped. Check the main beam tell-tale on the dash.
3. Left indicator, right indicator, then hazards. Count the flash: roughly one to two flashes a second.
4. Ask someone to press the brake pedal and check both stop lamps, then check they go off when the pedal is released.
5. Rear fog lamp on, and check its tell-tale.
6. Engine running, reverse selected: check the reversing lamp or lamps.
7. Check every lens for cracks and water, and both rear reflectors.
8. If you have a tow bar, test the socket with a trailer or a socket tester.

Most failures are a blown bulb or a corroded earth. Replace bulbs in pairs on headlamps so they match, and see why bulbs keep blowing if the same one keeps going.

Frequently asked questions

Is a reverse light an MOT failure?

Yes, on vehicles first used on or after 1 September 2009. At least one white reversing lamp must work when reverse is selected, and an inoperative reversing lamp is a major defect. Vehicles first used before that date do not have their reversing lamps tested.

Are daytime running lights an MOT failure?

Only on cars first used from 1 March 2018 where the DRLs were fitted as standard. On those cars a DRL that does not work is judged like a position lamp, which is normally a major defect.

Is a number plate light an MOT failure?

Yes, if the vehicle’s only number plate lamp, or all of its number plate lamps, do not work. If one of two is out, it is a minor defect and the vehicle still passes.

Is a blown brake light an MOT failure?

Yes. One stop lamp out is a major defect. No stop lamps working at all is a dangerous defect.

Are LED headlight bulbs an MOT failure?

On vehicles first used from 1 April 1986, an LED bulb in a halogen headlamp fails unless it is an approved LED replacement for that lamp with the approval sticker visible. Complete LED headlamp units are accepted if they meet the other headlamp rules.

Do tractors need an MOT?

No, tractors are exempt from the MOT. Their lights must still work by law, and some tractors used outside agriculture may need a goods vehicle test instead.