Rear fog lights wont work

You do know they only work with headlamps on ? Check h/book and see if covered by a fuse .

If thats a sign for 38 years into the future....
(sorry could not help it), seriously, if the fuses are ok the contact on the twisty pod can sometimes act up, I had to flick mine a couple of times on the C4

Check your bulb at the rear,and if your car has a tow bar then that could be the issue at the trailer socket,that's all I can think of other than what,s already been suggested:-)