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Trailer Wiring

d3athsong

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d3athsong Enthusiast

d3athsong

Posted
Posted

Ive gota question that the answer should be fairly obvious to, but you never know these days. Just bought an 08 gm 1500 2wd. It has the heavy duty trailering package and has the hitch and trailer plug at the back. Is all the wiring there for me to put a trailer brake controller in?

minibike132 Senior Enthusiast

minibike132

Posted
Posted

Hope this helps, sorry unable to post pics.

 

 

999999995.gifSubject:Information on Auxiliary Power Wire at Trailer and Installation of Aftermarket Trailer Brake Controller - Towing, Tow #06-08-45-008A - (09/18/2007)

 

 

 

 

 

 

Models:2007-2008 Cadillac Escalade, Escalade ESV, Escalade EXT

 

 

2007-2008 Chevrolet Avalanche, Silverado, Suburban, Tahoe

 

 

2007-2008 GMC Sierra, Yukon, Yukon Denali, Yukon XL, Yukon Denali XL

 

 

 

 

This bulletin is being revised to provide detailed steps for installing an electric trailer brake controller. Please discard Corporate Bulletin Number 06-08-45-008 (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, 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. The following steps should be used to complete the installation.

 


  1. <LI type=1> Locate the trailer brake control circuits that are looped and taped to the main harness under the instrument panel.
    <LI type=1>Pull the trailering wire harness down.
     
    <LI type=1>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

 

<LI type=1>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. <LI type=1>Break the tape on the red/black wire and pull it toward the front of vehicle. <LI type=1>Remove the lid from the electrical center.
<LI type=1>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: 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 steps 8.1 thru 8.4 to connect circuit #742:

8.1. Locate the red/black wire, looped and taped to the chassis harness, below the brake master cylinder.

 

 

8.2. Break the tape and route the wire to the front of the underhood electrical center.

 

 

8.3. 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.

 

 

8.4. 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.

 

</FONT>

 

 

GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.

999999994.gifWE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION

© Copyright General Motors Corporation. All Rights Reserved.

 

 

d3athsong Enthusiast

d3athsong

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Thanks for the info and quick reply. I was kinda hoping they had just stuck a plug under there that i had missed. I would have preffered not to play around with wiring but i guess thats how they build em.

walbern1 Enthusiast

walbern1

Posted
Posted

It's pretty easy really, all the wires are marked and in one bundle under the dash. The two wires under the hood at the electrical box are a little short so take your time when you are routing them.

d3athsong Enthusiast

d3athsong

Posted
  • Author
Posted

Ive looked and it looks pretty straightforward. Any suggestions for what a good controller is these days. Last one that we put in was back in 94 adn im sure things have changed as to what is a quality controller.

c4cruiser Enthusiast

c4cruiser

Posted
Posted

I use a Tekonsha 'Prodigy' controller for my car trailer. It has a good rep here and it's easy to connect given the wiring info above. It's simple to install and you can set trailer braking effort based on the towing weight by a simple push of a button. You can find then for around $100 at a number of internet sources.

 

It's too bad that GM decided to go away from the pigtail assembly and the connector in the block up under the dash. Tekonsha offers custom wire harnesses with specific connectors on both ends that made the whole install process a simple plug-and-play. But with the included harness you get with the Prodigy, it's easy to make the connections once you bend 3 different ways to get up under the dash....

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