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any trailer wire harness gurus?

monker

TY 4 Stroke Guru
Joined
Apr 15, 2003
Messages
953
Location
Chittenango, NY
I have an 04 silverado that I have been towing with for some time. My right rear trailer brake light has stopped working for some reason now. When tested with at 12v source the trailer is fine. Using a meter, there is no 12v coming from the 7 pin connector on the truck. As far as I can tell, fuses look ok, but I didn't see one labeled specifically for trailer brake lights.

Any sugestions?
 

Hey Monker, Hows it going?
Have you checked under the trailer for all the wires. when I went to get my trailer ready this year I had the same problem only with a few more lights. Turns out I have a woodchuck that seemed to think the exposed wires under the trailer make a pretty good snack. Had to rerun some wires and do repairs on others. Basically just replaced and fortified the wires so it would be harder for them to get to and weather sealed everything.

Good luck and hope to see you this year.

Boomer (Dale)
 
yeah, all the trailer lights work when I use a different 12v source. The problem is on the pickup somewhere. Weird thing is the turn signal uses the same wire and works fine.
 
I had the same problem with my Golf last week. The module that gets plugged in to the wiring harness of the car had trouble in it. Replace the module and all is good. Not sure if your truck has a similar setup
 
Well, I went through every fuse with a meter and all came up good. I guess is could be some module under there. Looks like a trip to the dealer. :o|
 
Try replacing the wire harness. It should be a plug in type. A clip on each side and put the new one in.
 
My father-in-law's truck had the same problem and we found it to be a fuse. Check your manual and see if you can track it down, the trailer harness uses a different fuse than the regular lights in the truck.

Good Luck
 
jim-bob said:
under the hood theres a box with additional fuses/ its probably one of those / red colored I believe / later

I had a similar problem with my '07 Tahoe when I installed ski guides on my trailer and accidentally ran a screw through one of the trailer wires. In my truck, there is a fuse box under the hood on the driver's side that uses mini-fuses. I cooked two of them. Once I discovered/corrected the problem with the trailer and replaced the fuses, all was well.
 
there are also trailer fuses in the fuse panel left side of dash when you open the drivers door . I work at a GM dealership.
 
You probably have a "high impedance" circuiit . Try hooking a light bulb up to the truck, my guess is it well not light. The meter shows 12 volts because it does not "LOAD" the circuit enough.
 


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