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Auto electrics
Auto electrical work covers everything the wiring does: lights, indicators, wipers, windows, central locking, the charging system and the immobiliser.
What auto electrics means
Faults are often intermittent, so most of the job is tracing where a circuit breaks rather than fitting the part at the end of it.
What the job covers
- Wiring loom fault tracing and repair
- Parasitic battery drain testing
- Lighting, wiper and window motor faults
- Immobiliser and central locking
- Towbar electrics and dashcam wiring
When you might need it
- A bulb that keeps blowing, or lights that dim and brighten as the engine revs.
- The battery goes flat when the car is left for a few days, which usually means something is still drawing power.
- Windows, locks or wipers that work sometimes and not others.
What it costs, and what changes the price
Typically £50 to £400.
- Most of the cost is diagnosis time, not parts. A fault found in twenty minutes costs far less than one that takes half a day.
- Wiring looms on modern cars are packed tightly, so reaching a damaged section can take longer than repairing it.
- Modules that need coding to the car add both a part cost and programming time.
How long it takes
A straightforward bulb or fuse is minutes. Tracing an intermittent fault can take several hours, and a good garage will agree a limit with you first.
What the MOT data shows
Out of 42,728,066 MOT tests in 2025, these are the parts covered by this job that testers recorded as faults.
| Part | Recorded in 2025 |
|---|---|
| Registration plate lamp(s) | 1,896,386 |
| Headlamp | 1,469,274 |
| Headlamp aim | 1,462,047 |
| Position lamp | 1,235,059 |
| Stop lamp | 880,483 |
Common questions
Why does my battery keep going flat?
Usually either the battery is near the end of its life, the alternator is not charging properly, or something is drawing current with the car switched off. A garage can measure which.
Is a blown bulb really an MOT failure?
Yes, and it is the most common failure in the country by a wide margin. It is also among the cheapest to put right.
Can any garage do auto electrics?
Most handle bulbs, fuses and batteries. Tracing a wiring fault or coding a module is more specialist, so it is worth asking before you book.