Williamsracing17

I have the towing package. It's a 2008 Z71 crew cab. I don't have 12 volts at my 12 volt supply coming out of my plug in the back. My enclosed trailer has lights wired up to run off of that power so I need it. I was told that there is a wire under the hood that I need to hook up. I can't find it to save my life!!! I've checked all the fuses and they all show to be good.

Suggestions?

Doug Roberts

Should go to fuse box then battery terminal last I looked no hidden wire back trace wire or run a new one could be broke

MDTAHOE

Bulletin No.: 06-08-45-008D

Date: July 12, 2010

Subject: Information on Auxiliary Power Wire at Trailer and Installation of Aftermarket Trailer Brake Controller - Towing, Tow

Models:
2007-2011 Cadillac Escalade, Escalade ESV, Escalade EXT
2007-2011 Chevrolet Avalanche, Silverado, Suburban, Tahoe
2007-2011 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL
2008-2011 HUMMER H2
Supercede:
This bulletin is being revised to add the 2011 model year and information about the orientation of the ringlet. Please discard Corporate Bulletin Number 06-08-45-008C (Section 08 - Body and Accessories).
Important
Installation of an electric brake controller and the wiring connections outlined in this bulletin are the responsibility of the dealership or customer. These repairs should never be charged to warranty. If you have any questions, please consult with your District Service Manager.
Some customers may have questions on how to connect an electric trailer brake controller or where the brake controller pigtail harness is located.

Starting with the new 2007 full-size utilities and pickups and 2008 HUMMER H2, there is no longer an electric trailer brake controller pigtail harness.

An aftermarket brake controller will need to be installed/connected to the blunt wires under the left side of the IP for vehicles built without JL1 - Integrated Brake Controller (full-size utilities and pickups). The following steps should be used to complete the installation.




1. Locate the trailer brake control circuits that are looped and taped to the main harness under the instrument panel.



2. Pull the trailering wire harness down.



3. Match the vehicle harness label circuit functions to the trailer brake controller jumper harness functions.
Important
The color or wires to be joined together may not match.
- Dark Blue Wire: switched power from controller to trailer brakes
- Red with Black Stripe: fused vehicle power to electrical brake controller
- Light Blue with White Stripe: Brake switch input to power electric brake controller
- White: ground
- Orange: CHMSL (Center High Mounted Stop Lamp) - not required with most systems



4. After completing the under dash connections to the electric brake controller, open the hood and locate the red wire that is taped to the harness between the underhood electrical center and the driver side front fender.
5. Break the tape on the red/black wire and pull it toward the front of vehicle.
6. Remove the lid from the electrical center.



Important
Ensure that the ringlets are not interfering with the UBEC cover.
7. Place the terminal on the larger of the two studs at the front of the electrical center and secure with an M8 nut. This is circuit #242 to stud #2, to power the aftermarket trailer brake controller.
Important
The fuse is already present in the vehicle to power the electrical trailer brake controller system.
Auxiliary Power (Applies to All LD & 07-09 HD's Only)




Circuit #742 for Auxiliary Power at the 7-way trailer connector is no longer connected by the GM Assembly Plant. If the customer desires auxiliary power at the trailer connector location (i.e. refrigeration, battery charger or interior light in the trailer), complete the following steps to connect circuit #742:

1. Locate the red/black wire, looped and taped to the chassis harness, below the brake master cylinder.
2. Break the tape and route the wire to the front of the underhood electrical center.



Important
Ensure that the ringlets are not interfering with the UBEC cover.
3. Place the terminal on the smaller of the two studs on the electrical center and secure with an M6 fastener. This is circuit #742 to stud #1 for auxiliary power to the 7-way trailer connector.
4. ONLY for vehicles without RPO TP2 - Auxiliary Battery, install a 40 amp fuse to power the circuit.
Important
For vehicles equipped with RPO TP2 - Devices powered by this fuse will drain the vehicle battery if left connected with the vehicle not running.

MDTAHOE

If you do not need the brake controller I think you can start with step 4. If you can not find the wire still you may only need to add the fuse. I hope this helps

Gundog

The wire should be on the drivers side in the engine compartment. Check just under the break fluid reservior. It is tied in a small bundle.

Williamsracing17

MDTAHOE, that was great!! I found the wire. I hooked it up to the already powered 30 amp circuit since I didn't have a 40 amp fuse. I still have no power at the back of the truck in my 7 way plug. What am I missing? Do I HAVE to hook up a brake controller?

MDTAHOE

Start where the directions say for auxiliary power circuit 742.


Circuit #742 for Auxiliary Power at the 7-way trailer connector is no longer connected by the GM Assembly Plant. If the customer desires auxiliary power at the trailer connector location (i.e. refrigeration, battery charger or interior light in the trailer), complete the following steps to connect circuit #742:

1. Locate the red/black wire, looped and taped to the chassis harness, below the brake master cylinder.
2. Break the tape and route the wire to the front of the underhood electrical center.



Important
Ensure that the ringlets are not interfering with the UBEC cover.
3. Place the terminal on the smaller of the two studs on the electrical center and secure with an M6 fastener. This is circuit #742 to stud #1 for auxiliary power to the 7-way trailer connector.
4. ONLY for vehicles without RPO TP2 - Auxiliary Battery, install a 40 amp fuse to power the circuit.
Important
For vehicles equipped with RPO TP2 - Devices powered by this fuse will drain the vehicle battery if left connected with the vehicle not running.


Use the 2 pictures in post #4. Make sure the red/black wire is on the right side post it looks black. Then you must put a fuse in the slot in the picture. I have never done to before so if it still does not work I can not help much more without seeing it.

Williamsracing17

Thanks for the help. I have it currently hooked to the larger stud and it has power at the stud, but not at the trailer hook up. Doesn't make since. I'll try to switch to the smaller stud and put in a fuse tomorrow, but I'm not too hopeful.

Thanks again.

holsonbake

Hi Guys: The white wire is goiund, the red wire is 12V. The blue/white wire is 12V all the time. So I thought this signale toggled based on the break switch. It's 12V all the time. Does anyone have a suggestion as to why the blue/white wire will not toggle between 0V & 12V? Of course someone will say replace the break switch! ok, but my rear break light toggles when I hit the break peddle. Anywhay let me know your suggestions, thanks!

dh

mountainmanjoe

@holsonbake
you're resurrecting a thread that was posted 12 years ago. None of these people are going to reply to you, so it's always better to create your own new thread than digging up these old ones.
At the very minimum, you need to post your vehicle info if you want help from people.