Troubleshooting P-2 Brake Controller Installation on a 2008 Chevy 1500

Question:

I purchased a Prodigy P2 controller, installing it in a 2008 Chevy 1500 Silverado. The video helps but, I have no power on the controller plug or at the bundled wires in the pickup. I have power at the fuse box stud, but at the other end of red wire none. What should I read for voltage at the red, and the blue wires the brake control wire reads varying voltage as the brake is pressed but no power voltage, so no voltage at the controller.

asked by: Allen M

Expert Reply:

Since there is no power at the bundled wires under the dash the problem is most likely under the hood at the power distribution box. The power for the brake controller is supplied from a wire that is located between the driver-side front fender and the power distribution box (see photo link). There is a ring terminal on the end of the wire and it should be ran to the left power stud located at the front of the power distribution box with a M6 nut, item # 185916.

If the wire is connected to the proper stud and you still do not have constant power to the 12 volt, red, wire in the vehicle bundle then you will need to either install or check the fuse that activates the power stud under the hood.

There is the possibility that you have the wrong wire connected to the power distribution post. If you connected the wire that is found under the master cylinder to the power stud then this is powering the 12 volt connection at the 7-Way and you will need to find the wire between the power distribution box and the drivers side fender.

The red wire going into the brake controller should show 12 volts only when the brake pedal is pressed and should be attached to the light blue wire in the vehicle brake controller wiring bundle. The Blue wire is the brake output and will not show voltage until it is connected to a properly wired brake controller and trailer, and either the brake pedal is depressed or the manual brake switch is activated. The blue wire should be attached to the dark blue wire in the vehicle brake controller wiring bundle. The Black wire coming out of the brake controller should be attached to the red wire in the vehicle brake controller wiring bundle. Finally, the white wire is connected to the white wire in the vehicle brake controller wiring bundle.

I have linked a detailed article below for installation of a brake controller on the 2008 GMC And Chevy trucks.

expert reply by: Robert G