Help. 07 Sierra 2500HD Duramax Brake Output to Trailer Not Working

[ng2951]

Hello,

I was installing the Prodigy P2 brake controller and the controller is showing .n.c with the trailer connected. All the lights work fine on the trailer only the brake side shows NC.

The truck (2007 Duramax Sierra 2500) has two bargman 7-way connectors: one in the bed, one on the bumper. I suspect the previous owner used the turnover ball in the bed along with the bargman connector there when he towed. I don't know if either the bed or bumper bargman work.

Since I lack any real wiring diagrams I don't know if these bargmans work in parallel or if there is a jumper to engage to select one ot the other. There is also a small wire with a weatherproof connector behind bumper bargman umbillical. I don't know where it is suppose to plug in or its function.

The people at Camping World also thought the 02 Sierra controller cable works with the 07 Sierra. I did check the pins in the block under the driver side control panel and they match up but I don't know if they are correct.

I read on another website something cryptic about some fuses that may be under the hood on the driver's side that work with the output of the brake controller. Does anyone know which ones these might be?? The cover of the fuse compartment is not all that helpful...


Ideas???

[herk7769]

I have the manual you are looking for (2008 version though); but it is 37 megs and too large to upload.
I downloaded my copy from here:

Electrical Manual

There is LOTS of great info on the trailer connectors and the brake controller pre-wiring.

Oh it is compressed using the RAR format. You can get a free "unpacker" at www.download.com

[ng2951]

Thanks. Tracked it down to bad pin behind the bargman connector.

[ng2951]

...The people at Camping World also thought the 02 Sierra controller cable works with the 07 Sierra. I did check the pins in the block under the driver side control panel and they match up but I don't know if they are correct...

Turns out CW was wrong. in 03 GMC moved the brake pedal input (red wire) to the opposite corner of the connector.

FYI-Prodigy'w wiring diagram for the cable is also wrong for the 3015-P cable. It shows the identical pinouts for the 3025-P cable...

[herk7769]

Glad you figured it out!

Happy Camping!

[ng2951]

Thanks. Tested it tonight and it works. Biggest problem was getting the pin out. Easy once you know how, but its better to have the correct connector in the first place...