Weak rear lights cluster

[sacramento7788]

Hi

Rear left light cluster working but very dim. I have looked locally and all the contacts are seemingly in good shape. Any ideas what else it could be?

Any help would be appreciated.

[john.p.clegg]

Earth (ground)

John

[TeeJay]

As John suggests, its very likely to be the black earth wire/s.
Look for a cluster of black wires that are typically bolted to the boot floor onto a alum bobbin. Remove, clean wires, apply Vaseline and tighten back up.

A quick check is to attach a suitable wire to the battery ground post (negative, but if early car like my 1968 it could be positive) and attach other end to the black wire at the light or a metal part of the light. If light shines brightly when switched on, you will known its the earth wires.