freight train

So a couple weeks back I took Freight Train to work to haul some flooring for work. I noticed that all of the bed running lights wasn't working. So with school not in I had to take the week off work to watch my son. So today I was able to get away from dads Ferguson's long enough to finally dig into it and troubleshoot the lights. So I started at the blue RWAL plug and worked my way back and sure enough I had voltage all the way back at the two plugs for the tail light plugs. Here is where it gets tricky. I have had my hands on many a 1st gens and I have never seen this harness before. I had to drop the spare tire to see it but there was this relay harness plugged into it. So I had power to through the black/yellow wire for running lights but not out of it. So I traced the red wire going into the relay plug and it went up to the battery where it had a 25amp fuse holder with a blown fuse. So I installed a new fuse and sure enough the bed lights worked but not the tailgate. I started troubleshooting that and soon as I unplugged that power wire going into the tailgate I had power. So as soon as I started trying to push it in it blew the fuse again. Then it got dark. Tomorrow I am going to pull each light out and tape a wire to their plugs and then carefully pull the harness out of the tailgate to see if there are any shorts or bare wires touching the inside of the tailgate. Anyways, I snapped two pics of this little relay harness that I have never seen before. Does anyone know the exact purpose of this harness and if its Mopar?

freight train

Okay so no one has seen one of these before LOL. C'mon Oliver. I know if there is a guy on here who has had their hands on more 1st gens then me its you. Have you seen one of this before? On a side note I did get everything right on Freight Train this morning. As soon as I unplugged the lights and started pulling the harness the cause of my symptoms revealed itself. It looks as if at some point over the years someone has tried to pull the tailgate off without knowing how to properly do it. This caused the little rubber isolator to come out of its holder which then allowed the black/yellow wire to become cut through years of me opening/closing it. I pulled the tailgate (properly) to get better access to the harness. I cut the damaged harness out and soldered in a new wire and then heat taped it to insure years of corroision free service. Electricity is a funny thing.

oliver foster

RAM,
The tag that says "A" on that wire harness looks like a wire harness I just saw while working on one of the '92/'93 cabs that had a taped on 'B", that looked the same style tape and print job.
So it certainly could be a factory harness.

I will see if either of the '92/'93 W-250 frames in my shop have that wire harness on them.

Sorry I can't be more help than that currently.

freight train

Oli I cant say one way or the other to be honest with you. I agree that the shething and paper tape that had the relay/connector taped to the RWAL harness and along with the shething on its power wire all the way up to the battery and it has the identical fuse connector as does the power wire for the underbed trans cooler dad has on his one truck he bought new in 1992. I know this is trivial but I FREAKING LOVE FINDING ODDBALL THINGS ON THESE 1ST GENS! Have you personally ever seen a relay back at the end of the RWAL harness like this one? I mean it could be an aftermarket item made to be a very simple plug and play to stop a short in the 7-pin trailer plug from shorting out the trucks exterior lighting. Over the years I have either owned or been under close to 30 1st gens and I have never seen it before. Heck I have owned this truck since 2004 and until I dropped the spare to get a better look at the taillight pigtails I didn't even know it was there, LOL.

mopar2ya

I’ll go look at mine. The dealer installed a OEM “overlay” harness on min, as pulling a trailer with more than 2 lights was burning up headlight switches.