Brake Controller Only Working when Using the Manual Override
Question:
I just transfered my powertrac brake controller from my 1999 GMC sierra to my 2006 2500HD duramax. THe light comes on when I plug in the trailer plug, but when I mash the brake, the trailer brakes do not work. However, I can slide the button that fully engages the trailer brakes on the brake controller and that works.
asked by: Austin
Expert Reply:
First thing I would do is use a circuit tester, like part # PTW2993, to check the red wire coming out of the rear of the controller to make sure you get voltage when the brake is pressed. If not, you might have a blown fuse in the power distribution box under the hood. The brake controller gets its input from the CHMSL circuit, which is the third brake light on the rear of the cab. If this light is not functioning as well, the fuse is the problem.
Your owner's manual should be able to tell you the location of the fuse for CHMSL.
