How Does P3 Brake Controller Replace Integrated Controller of 2014 GMC 2500HD

Question:

I have a 2014 GMC 2500HD with the integrated brake controller. Should the P3 wiring be attached to the wiring coming from the integrated controller? There are 6 wires on the plug to the integrated controller. They are not near the size gauge of the wires on the P3.

asked by: Michael K

Expert Reply:

If you check out the attached link below you'll see all of the steps needed to install a brake controller in your 2014 GMC 2500HD with an integrated controller.

The 2007(new body style)-current models have four or five blunt-cut wires under the left side of the instrument panel. These wires are located above your left shin as you are seated in the driver's seat. The wires can be identified by a white label and the color of the wires. The wire colors are (1) Red/Black wire, (1) White wire, (1) Light Blue/White wire and (1) Dark Blue wire, and possibly (1) Orange wire. See picture.

Connect the brake control to these wires as follows.

GM Wire to Brake Control Wire Function
Red/Black to Black Battery Power
White to White Ground
Light Blue/White to Red Brake Light Signal
Drk Blue N/A Brake Control Output to Trailer
Orange N/A Center High Mount Stop Lamp (CHMSL)

Using enough 12-gauge wire like part # 12-1-1 to reach the rear of the truck, connect one end to the Blue wire on the aftermarket brake control. Run the other end of the Blue wire in conduit or loom to the 7-way trailer connector. At the 7-way trailer connector you will have to remove some tape and pull back the plastic loom to access the factory-installed Blue wire. Cut the factory Blue wire approximately 4 to 6 inches from the trailer connector. See picture 2.

Connect remaining end of Blue wire from aftermarket brake control to the Blue wire going to the trailer connector. After connection is made, heat shrink, reinstall plastic loom and re-tape loom.

To complete the installation, two wires under the hood have to be connected. One is the power supply wire to the aftermarket brake control. The other is the battery charge line to the 7-way connector. These wires are both Red/Black with eyelets connected to them. They are coiled up under the hood and must be connected to the under-hood fuse box. The brake control power wire is located between the fuse box and the left (driver's side) fender. The battery charge wire is located under the master cylinder/brake booster assembly. See picture 3.

The battery charge wire will go on the smaller Black stud, and an M6X1.0 metric nut is required to attach the wire to the stud. Larger posts require an M8 nut. The brake control wire will go on the larger Silver stud along with the existing Red wire. The existing Red wire is the power wire for the factory brake control and does not need to be removed.