'08/'09 H2 Trailer 12V Power ... ?
 

Has anyone found the 12V trailer power cable (w/eyelet) in their '08/'09 model H2?

For those unaware, trailer wiring has changed in the '08/'09 models. The brake controller is no longer pre-wired to the fuse box like the '07 and earlier models ... it was plug 'n play on my '05 SUT.

Anyway, I found a lone red/black stripe wire coming out of a wire harness on the driver side of the brake master cylinder (pre-wired power for the brake controller). Pulled it and found the eyelet taped to the outside of the harness directly next to the brake booster. Pretty simple .... this is power for the trailer brake controller. I connected it to the larger tap in the front of the under hood fuse box, installed the 30A fuse and wired the controller to the blunt end wiring harness under the dash ... I now have a working brake controller!

Now, for the life of me, I cannot find the other red/black striped wire with eyelet to power the 12V to the trailer. This will be connected to the smaller tap in front of the under hood fuse box and powered by a 40A fuse. Supposedly, it is in the harness between the under hood fuse box and the driver's side fender and runs directly to the 7-way trailer plug ... no such luck. I confirmed that there is a red/black striped wire at the trailer plug for 12V power. Has anyone found this wire under the hood that could post a photo of where it is????

If I no one can help, I will just end up running a new wire to the back, but I would rather use the factory wire.

I'm not sure the wire goes to the harness to be connected to that lug. I only think this because user manual says when you put H2 in tow haul it then sends/actvates that voltage to the trailer/wire in question. So i think the BCM is the activating the wire. If you have volt meter you could test it. I don't have trailer brakes installed but I'm curious. Maybe a guru with the right connections can confirm or deny.

I do know the red/black you found goes through the BCM or whatever control module. So that power may be split or something to make it happen. I tested mine without it fused I could not locate fuse after I removed it a few months ago. I'll look more for it.

So I had my CB connected to that wire. That connection left me having the Hummer towed. Short story if I left the CB powered on with ignition off it sometimes would blow a 2amp DLIC fuse under the hood. H2 would not start until I replaced it. Has something to do with factory antitheft.

There must be two-wires .... I currently have one red/black wire connected to one of the posts with the proper fuse installed (labeled brake controller). Since I have power to my brake controller under the dash, I have the "brake controller wire" connected.

There must be a second wire for the other post for power to the red/black wire at the seven-wire plug in the back. There is a wire from the wiring harness going to the seven-wire plug in the back so the other end must be under the hood somewhere.

The Owner's Manual says "If you are charging a remote (non-vehicle) battery, press the Tow/Haul mode button located at the end of the shift lever. This will boost the vehicle system voltage and properly charge the battery." It does not say anything about the tow/haul mode "activating" the 12+ power to the seven-way plug. By the way, I already tested it and the post is "hot" whether the tow/haul mode is on or not.

Man I wish I could help. I went through a bit of this wiring my 03'. the power to my brake controller was not working properly (loose connection under the fuse box) and had to test light the system. was a pita.

Now that we have stored our toy hauler, I will get back to searching for the 12V power. I ran a temporary wire straight back to the plug, but I would rather find the stock wire.

Check this out,

http://www.justanswer.com/chevy/24m6...rs-manual.html

Yep ... downloaded and printed that before I even opened the hood to start this "project"?

It seems the biggest problem is these wires are not consistently located from vehicle to vehicle.

I found my second wire. It was/is taped down on another wire harness loom... below and forward of the first one. I got pics if anyone wants them posted.

Just seen this post, if you are still here, pleases post a pic.

Praying you will post the pics, I can't find it either, arghhhh