Trailer brake/turn lights work but the running lights don't. I've checked the fuses and they're good. I know the trailer lights work.

Anyone know the color of the wire at the plug in that powers the running lights? I need to trace it and see if it's shorted or even hooked up.

TIA...

 

Just replaced the trailer plug on my wife's horse trailer due to corrosion and had to go through each and every wire to find the right color/light combo. Especially since her running lights didn't work, though I knew they were good.

This will be more than your asking, but... every truck has different wiring colors doing different functions. Who knows why...

First, turned the truck to face the trailer ground the horse trailer to the pickup with the black jumper cable. Used an 18 gauge lead wire connected to the hot terminal of the truck battery, and with the plug on the horse trailer opened up, I touched each wire with the hot lead to get the lights to turn on. Annotated which color wire in trailer harness went to which lights, and where each hooked into the plug socket.

Second, turned the truck back around and ground the truck to trailer in the same manner. Used the same "hot wire" with alligator clips and by process of elimination, found out which wire in the truck's trailer harness did what. Did this by connecting one end to a KNOWN wire in the trailer harness, (e.g. running lights) and have the wife work the lights in the truck until I found a match. One of the wires coming out of the truck's trailer wire harness is for auxillary, and that is what ran the trailer lights on my wife's trailer.

May be a simpler way to do this, but as I was replacing the plub on the trailer, this is what worked for me.
Dave

 

Thanks for the info ride a hd.

I was trying to avoid doing what you did, but I guess there's no easy way.

I think I'll just plug a hot wire into the trailer plug until the running lights come on and find the coressponding socket/wire on the truck side and trace it.

 

Black/orange is the dedicated 12v for the trailer circuit. There is a separate fuse for it in your PDC.