1986 M1009 Rear Light Nightmare

[TrashyRacoonKing]

I just told ya!! Front turn signal...it's up top of the coolant res or just in front of the front battery...could be the bulb socket internal side ground too...take bulbs out and see if things change.

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Checked the front grounds. Found one in each spot you said, thank you for that. Disconnected both grounds. No change to the rear lights issue. Disconnected and swapped bulbs, no change to rear lights issue. Disconnected headlights, no change to rear lights issue. BUT I happen to find a unknown cable. So help me if this is a random ground thats been severed. Anyone have any idea what it is? Comes out of the same stalk of wires the front headlight connects to.

 

[deank]

Not sure what the unknown connector is.
The brown wire with the rubber head on it goes to the brake sensor (cannot remember the correct name for the part) under the radiator on the crossmember.

 

[TrashyRacoonKing]

Not sure what the unknown connector is.
The brown wire with the rubber head on it goes to the brake sensor (cannot remember the correct name for the part) under the radiator on the crossmember.

Awesome! The flat connector goes into the break sensor wire. Trying to figure out where the rear wire goes now. Im hoping this is what is causing the issue. I doubt it, but who knows.

 

[TrashyRacoonKing]

Update because it was a glorious sunny day:

Found a total of 5 grounds for the lights. 2 in the front, one located next to the coolant res, and one located infront of front battery. Thanks to @WWRD99 for their location. Checked both, cleaned both. Found 3 in the rear, one behind each tail light, and the one behind therear fender that connects to the truck bed. Thanks for @nyoffroad for that one. All have have been cleaned and reset with new screws. I split and checked the electrical block on the fire wall. Took it apart and cleaned a lot... I mean A LOT of black goo from the insides. Bent a few pins back to their original position, and screwed it back in. I've replaced all the bulbs, checked all the sockets, replaced all the fuses. I am still getting the same symptoms, I am at a complete loss. I am getting the 12v to 5v on the sockets but only when hooked to the wiring harness. That rear wiring harness is pushing feedback from somewhere. Short of asking if anyone has any further ideas, anyone ever use a shop in El Paso for their CUCV? Google has given several results but they are all for regular cars and trucks... I have some fear from reading several of the horror stories on here about people screwing up a persons CUCV.

 

[Barrman]

You are now it seems down to what the Technical Manuals calls “Trace wiring.”

I know you wrote that the wiring between the firewall and the rear sockets looked ok. But, somewhere some wires are touching.

 

[TrashyRacoonKing]

I hate trace wiring... Next Friday I have off. I am just going to take it apart. Remove the sockets and test them out of the truck, take apart the block, and undo the wires. Give the fuse block another good cleaning and check the fuse fit. Find where the culprit is and fix it. Thanks for the help everyone. I'll update everyone next weekend if I can find the issue. I know I am overlooking something small and that is what kills me.

 

[TrashyRacoonKing]

Gents... Last update. Somehow.... Someway.... It fixed itself.

Only thing different I did was recheck and put in brand new fuses.... again. It works. I would like to thank each and everyone of you from the bottom of my heart. This is why I came back to steelsoldiers. Hope I'll get to be the one answering a question here in the future.

 

[TrashyRacoonKing]

SHE PASSED INSPECTION! READY TO GET HER ON THE ROAD!!!!