Troubleshooting Brake Controller Thats Not Operating Trailer Brakes with Brake Pedal

Question:

My brakes operate when manually applied, however they will not apply with the brake pedal. I can hear a buzzing at the drum when brake applied. Any suggestions.

asked by: John M

Helpful Expert Reply:

How to proceed will depend on the year, make and model of your vehicle and the brand and model of your brake controller, but I can provide some generalized troubleshooting strategies for you.

If your brake controller is a proportional model, you will NOT get power to the trailer brakes with the brake pedal unless the vehicle is moving. A proportional controller has an internal sensor that can determine how quickly the tow vehicle is stopping. It will send the appropriate amount of voltage to the trailer brakes so the trailer and tow vehicle brake at the same rate.

If you have a time delayed controller, you should get activation of the trailer brakes using the brake pedal if the vehicle is stationary.

Hearing buzzing or humming at the trailer brakes is normal.

You can test the controller with a circuit tester like part # PTW2993. Test the red wire exiting the rear of the brake controller to make sure you're getting power on that wire when the brake pedal is pressed. If you're not, make sure the third brake light or CHMSL circuit on your vehicle is operating correctly. If it's not, check the appropriate fuse and replace as needed.

I've linked you to our brake controller troubleshoot FAQ article, as well as a video that shows how to troubleshoot a brake controller.

expert reply by: Mike L