A required lamp isn't lighting. Which classification it gets depends on which lamp it is and whether any of the pair still works — a single dead number plate bulb is treated differently from both brake lights being out.
Wording as it commonly appears on an MOT certificate: “Offside or nearside lamp not working”.
What does it mean?
A required lamp isn't lighting. Which classification it gets depends on which lamp it is and whether any of the pair still works — a single dead number plate bulb is treated differently from both brake lights being out.
How serious is it?
Usually recorded as: Minor, Major. The tester assesses the actual vehicle on the day, so your certificate is what counts.
What normally causes it?
- A blown bulb, which covers the large majority of these
- Corroded bulb holder contacts, common on rear clusters that let water in
- A blown fuse or a failed relay on indicator circuits
- A chafed wire in a boot lid or tailgate loom, where the harness flexes every time it opens
- On LED clusters, a failed module — you can't just change a bulb
What a mechanic would check
Bulb out and inspected first, then the holder for green corrosion and the contact spring for tension. If the bulb and holder are fine, I'd back-probe for voltage at the connector — that tells you in seconds whether it's a supply problem or the lamp.
What might need replacing
- A bulb
- A bulb holder or rear light cluster
- Wiring repair in the tailgate loom
- An LED light unit on newer cars
Can you still drive it?
It's a failure and it's also an offence to drive with required lights out. The saving grace is that it's usually the cheapest thing on the certificate — often a bulb and five minutes.
Repair cost
A bulb costs very little. A sealed LED rear cluster on a modern car is a genuinely expensive part, so it's worth knowing which you've got before assuming it's a cheap fix.
Before the retest
Walk round the car with someone working the switches: dipped, main, sidelights, indicators, hazards, brake lights including the high-level light, rear fog and number plate lamps. A new headlamp bulb or unit should be followed by a beam aim check, because a correctly working lamp aimed into oncoming traffic still fails. Wipe lenses clean and make sure no warning lights stay on after start-up.
Retest rules
If the vehicle stays at the test centre for repair and is retested within 10 working days, a partial retest is often free; some items qualify for a free retest if you bring the car back by the end of the next working day. The exact conditions are set out on GOV.UK, so confirm with the test centre before you leave. A major or dangerous failure means the car cannot legally be driven away unless the previous MOT is still valid and nothing dangerous was recorded — check your certificate first.
Related help
More lights failures · MOT failure decoder · Ask a mechanic about your certificate
This is general guidance from a UK mechanic, not a substitute for a physical inspection. Only the tester who inspected your vehicle can confirm what was recorded and why.