Bought a KA 2006 recently and as per tittle reverse light and lighter point aren't working.
Checked the light bulbs, there fine.
Took it to Halfords and was told that connector in reverse light is fine
Fuses are fine
Voltage is ok

Repair man told me that it's likely to be the earth points and to get them cleaned but I cannot find any diagrams anywhere, tried google and various forums.

If anyone could point me to where I can find them or what else it could be I would appreciate it.