no power to my trailer plug

[Diesail]

If you have nothing at all at the connector then the harness has been compromised in some way. The harness of the plugs into the back of the connector, that would be the first place to look. From there I would simply follow the harness forward and check for issues.

[TRCM]

I thought the same thing, I had a broken wire, but did some more researching, and this is what I found:

 

 

Check under your master cylinder. The pic earlier in this post alludes to the red wire between the fuse box and the fender as being hooked to stud 2 to get the 12v constant feed to the connector in back. That wire is ONLY for an aftermarket brake controller, and WILL NOT give you the 12v feed at the trailer connector, and should not be connected if you have the ITBC.

 

There is a larger gage red wire under the master cylinder, taped to a harness in much the same way. Connect this one to stud 2, and you WILL have 12v to the trailer connector (once you put in the fuse that is).

 

 

Look here:

 

http://www.gm-trucks...80&hl=aux+power

[jandersinc]

I believe the OP is saying he's had power and lights to the connector in the past, but all of it (power and lights) stopped working recently and he hasn't figured out why yet.