Hello All,
I'm hoping someone can help me with a vexing problem.
This started out with the heater fan not working. Tracing wires, continuity checks, voltage checks, etc. come to find out heater switch not getting power. Run new wire from #16 fuse to switch. Have fan, no temperature control. Brrrr. Dig deeper into wiring. Find hack "repair" with a butt connector that caused initial problem. Fixed that and now have fan AND heat. YAY!!! BUT...
In moving around fuse/relay board I managed to bring the Prince of Darkness to my headlights.
What I have determined is that the Light Relay is not being energized and so is not passing current to the headlights and parking/tail lights. Park/tail/instr lights work in first position of headlight switch but NO headlights/park/tail/inst. lights in second position.
My Qs:

1. Can someone direct me to a good wiring diagram for a 1992 740? I have one for a '90 740 and a '92 940. Both helpful but not exactly correct.

2. Where do the yellow/white wires off the side of relay go? One heads to the fuse for rear foglight if I remember and the other goes into the BIG bundle heading into the jungle under the dash. This is wire is the one I suspect.

3. If I'm wrong in #2 can some tell me which wires to trace/check for closing the relay. I have power in the big RED wire but nothing to the yellow/whites. Currently (NPI) I'm jumping the relay to get headlights and putting the headlight switch in the first position to get tail/parking/ instr. lights.

I look forward to your replies and THANK YOU!!! JB