help. 740 rear light electrical issues.
 

I hope someone can help, because this is stumping me. I have an 87 740 with some electrical issues.

My tail lights were working and somehow they shorted out. My running lights, tail lights and brake lights went out; everything except one running light on the back right. My front lights work.

I replaced the connection boards that the lights mount to, I checked all fuses and wiring, had the wiring diagram printed out and used that and.. nothing.

I am totally stumped and hope someone knows some kind of solution.

sedan or wagon? wagons can have issues where the wiring harness goes over the hinge.

I think I'd check for voltage at the various fuses when the corresponding light is supposedly turned on. if there's power at th efuse,s but not in rear, then its likely a wiring problem in between. if there's no power at the fuse, then its more likely upstream in the switches and stuff.