Bypassing the Factory Brake Controller on a 2007 GMC Sierra New Body Style

Question:

I have a 2007 GMC Duramax with the factory tow package. The factory brake controller has stopped working. Since it only works with electric brakes I want to install a Tekonsha P2 that would allow me to convert my fifth wheel to E over H brakes. My question is what do I need to do to disable the factory controller and install the P2? Will I have to remove a large portion of the dash to access the wiring? In your how to videos the process is always to simply find the taped up unused wires under the dash near the brake pedal. Then you just connect the wires to the P 2 controller. The wiring to the dash mounted factory controller are buried out of sight! Help

asked by: Mike R

Expert Reply:

There are a couple of things you need to be aware of. First, 5th wheel trailers have electric brakes. To use electric over hydraulic brakes you would have to completely run brake lines from new hydraulic brakes to the actuator.

Second, there isn't really a good place to mount the actuator on a 5th wheel trailer. I am not saying it can't be done but it won't be easy.

I assume that your 2007 GMC Sierra is a New Body style since it has the factory brake controller. The wiring you need is separate from the factory brake controller wiring. The wiring you need is up under the dash to the left of the steering column and held together with a white tag that describes the wire functions.

To hardwire in a brake controller the GM red/black wire goes to controller black. GM white to controller white. GM light blue/white to controller red. None of the other GM wires will be used.

The brake controller blue wire will need to be run manually from the controller to the back of the 7-Way and attached to the 7 o'clock position (remove the wire that is already there and tape it up out of the way). I recommend using about 20 feet or so of wire # 10-1-1 which is sold by the foot. You will need to route the wire through the firewall. Look for other wiring that goes through the firewall in order to run that blue wire through. I have included a link to a help article that explains this installation for you.

The P2 brake controller # 90885 is an excellent choice. Whether you go to electric over hydraulic brakes or stick with just electric brakes the P2 is up to the task.