Help with mystery wire identification

[Zeus51]

The blower motor grounds through the box it is mounted to. Most times the members here will tell you to run a second ground from the blower motor to another ground point (negative bus bar). That is what I did.

the horn is self grounding by the mounting bolt, just remove the horn and clean the bolt, horn where it bolts on and the point on the radiator support where it bolts on.

can you do a continuity check through the left side marker? All lights and power off, check continuity through both wires with the bulb in place.

I am still pondering all the light issues. I will get back to you on those.

I’m not sure how to check the continuity with the bulb in place. See pic. I can’t get my meter leads to a place on the wires. Would you cut the wires again and then do it? I did check continuity with bulb out and placed one lead on the ground piece and the other on piece that pinches the bulb. Does that work or just test the actual socket? i was thinking the socket. It checked out fine and the bulb works too

 

[Zeus51]

All of the rear lights share BRN-9A for power.

There may be one weak point in all of this, the fuse panel itself with the bulkhead connector. Have you done anything to take it all apart and clean all the contacts and tighten up the fuse connectors? I have completely gone through the whole thing on mine and found several fuse holder contacts that had to be adjusted.

I have not taken the fuse holder off but I did ensure the connectors were all clean. I’ll pull the fuse panel start cleaning. That’s a good idea

 

[Zeus51]

I have been reviewing the wiring diagrams. The voltmeter light is strange, but as it is supposed to be connected to the light for the heater control also, please see if it is blinking as well. Power for that circuit comes from the light switch to the bottom left fuse then provides power for all of the backlighting in the cluster.

Front and rear turn signals have separate circuits. They do not cross.

All four front turn signals/marker bulbs all share the Brown -9A that brings power from the headlight switch.
The front left turn/markers share LT Blue-14A that goes to the left turn indicator in the cluster to the turn signal switch back out on Brown -27 to the flasher at the top left of the fuse box

Thee right front turn/markers do the same thing but use DK Blu-15A

This is excellent info that I can use to trace voltage at certain points.

I’ve pulled the headlight harness out of the loom all the way back to the wiper reservoir and didn’t find any breaks or something that looked like issues. I’m starting to think my issue either at the fuse box or under the dash somewhere like you suggested. So I’ll start tracing the first day I get

 

[deank]

Just looking at the wiring again. If you take the bulb out of the left front turn/marker you can check for continuity on the bulkhead connector on the LT BLU -14A and the BRN-9A to test the sidemarker circuit. Disconnect the bulkhead connector first.

 

[deank]

Just a thought, you can also check the continuity without the bulb. Just check from each side of the bulb socket to the corresponding wire at the bulkhead connector with the bulkhead connector disconnected. Front bulb removed also.
How is the snow?