Trailer Wiring Issue

[Soundguy]

i'd also check ground first. use a set of jumper cables as the test.. clip to truck and trailer frame

 

[Diamondpilot]

If the trailer has brakes many of the early 2000's GM were wired wrong, or differently. I also sell trailers and have ran into this a few times. I have also seen many of the GM 7 pin round plugs internally corroded causing issues.

Chris

 

[brokenknee]

Here is a link to etrailer on how to trouble shoot wiring problems.

Trailer Wiring Diagrams | etrailer.com

Let us know what you found.

 

[turbo660]

If the trailer has brakes many of the early 2000's GM were wired wrong, or differently. I also sell trailers and have ran into this a few times. I have also seen many of the GM 7 pin round plugs internally corroded causing issues.
Chris

I had a similar problem with my 1999 silverado 1500, all I needed to do was unplug the wiring harness at the back of the 7 pin connecter, clean the corroded contacts and plug back in . Worked fine ever since.
Easy to check no cost solution.

 

[Soundguy]

on my 2000 yukon, I had to swap a wire inthe trailer plug adapter. that fixed it for me.