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.
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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.