2007.5 GMC 3500 Integrated Brake Controller Not Working

Question:

Ok I have a 2007.5 GMC 3500HD diesel with the integrated brake control, when I hooked up to my fifth wheel it used to show on the DIC trailer connected and when I pressed on the brake the led dots would increase with the amount of pressure on the brake, now Im getting nothing, no trailer connected or dots when pressing the brake, I have a trailer emulator that I plug in to the truck and all the lights go on except for the brake controller light it pulses, anyone have any ideas? Thanks

asked by: Charles L

Expert Reply:

There are a couple of things you can do to try and troubleshoot your GMC 3500.

First, I recommend making sure that the emulator you are using is compatible with GM trucks. The emulator that you mentioned # C73NR works only with some controllers. Sometimes, the LED lights on the emulators don't have enough draw to fully trigger the brake controller. A circuit tester with an incandescent bulb, like # PTW2993, will have enough draw to test the wires one the connector at the rear of your vehicle.

Another thing you can do is to find someone who has a truck and brake controller that are both functioning properly. Have him hook up his truck to your trailer to make sure the problem is originating on your truck and not your trailer. You could also connect your truck to a different trailer that has brakes that are working correctly to test this.

I also recommend getting under your truck to check your wiring. You will want to make sure your wiring is free of any corrosion, debris, and damage.

If none of these troubleshooting steps provide a solution for you, I recommend taking your truck to a local GM dealer.

expert reply by: Victoria B