Troubleshooting Euro rear foglight

[Klooney]

I have a 91 316i. I think I have the problem narrowed down to the switch or the relay. It appears someone has opened up the switch as there are tool marks on the pins. When I press the rear foglight button the instrument cluster light will sometimes flash orange, sometimes not light up at all, and sometimes hold steady. I’ve swapped relays between the front and rear fogs without any change. Is there a specific/different relay for the rear fogs? I don’t have any issues with the fronts.

[323i E30]

Could the main headlight switch be involved with your issue? The low beams need to be on for the rear fogs to function, which doesn't apply to the fronts.
I suck with electronics, but thought I'd mention it anyway.
Rear fogs is relay K4 (7.5 amp fuse @15) and front fogs relay K8, according to the fuse diagram.