How to Bypass Factory Brake Controller on 2008 GMC Sierra and Install Aftermarket Controller

Question:

I have a 2008 GMC 3500 dually and the integrated break controller is not working right. I am looking to replace the factory system with the Tekonsha prodigy. Do i use the wires under the dash for power and brake and run a seperate blue wire to the 7 way on the bumper to make it work or is there a seperate accessory plug to buy?

asked by: Spencer T

Expert Reply:

It sounds like you've got a good handle on what you need to do. The brake controller (like the Tekonsha # TK90160 Primus) would install using most of the tow package wires under the dash. The controller connects to the tow package harness as follows:

-Red/Black striped tow package wire connects to black wire on controller
-White wires connect together
-Light Blue/White striped tow package wire connects to Red brake controller wire
-The orange and dark blue tow package wire aren't needed

-The dark blue brake controller wire is extended with a length of # 12-1-1 wire and ran through the firewall down under the vehicle back to the trailer connector. Cut the blue wire exiting the rear of the 7-way trailer connector-be sure to leave enough room, at least 6 inches or so, so you can connect the cut blue wire leading to the trailer connector to the 12 gauge wire ran from the brake controller.

This process is outlined in the article I've linked for you. You might also need to complete the wiring under the hood at the fuse box as shown in the article.