rear brake light, is there a relay that controls them?

[Finisterre]

The rear left side lights have been dim for a while. I assumed a faulty earth was the problem and left it at that.
The rear left side light is now working okay but went out for a week.

I have applied a voltage across the bulbs through the metal framework they sit in and the bulbs are fine. The earth is fine.
The fuses are fine. I think the problem is the supply of electricity to the bulbs through the wiring.
The brown earth cable looks like it has run hot for a while.

The problem is intermittent.
Does anyone have a decent wiring diagram link?

cheers

[Finisterre]

spaghetticoder doesnt seem to work for me.

[Finisterre]

new roundel and cable end connector did the trick.
I bought the correct connector and surprise, official BMW block had to be cut down to fit, but there you go..