Troubleshooting Electric Trailer Brakes That Do Not Engage

Question:

I have a trailer that has electric brakes. For some reason I cant get my brakes to work. I have brake lights and the rest of the lights work. Just no brakes. I checked all my fuses on my truck and everything is working fine. What could be the issue? Thank you.

asked by: Chris J

Expert Reply:

Electric drum trailer brakes get their power from a dedicated brake circuit in the trailer wiring. On a vehicle 7-way type trailer socket (please refer to the linked photo) the trailer brake signal is carried on the contact at the 5-o-clock position.

You can test the socket for the correct signal by applying a circuit tester like # PTW2993 while a helper presses the manual override on the controller, with the controller set to maximum power. Please refer to the linked video for help in using a tester. If you detect a signal on the vehicle socket, then the issue is likely to be on the trailer.

You can also directly test the trailer's brakes just by applying power from a 12V battery (the one in your vehicle or a spare if you have one in the garage). Apply the ground and 12V+ connections to the appropriate contacts on the trailer's 7-way plug. You should be able to hear the brakes hum lightly when they receive power, and of course, you should feel that the wheels will not turn when you try to rotate them by hand.

You can refer to the linked articles for more help, but feel free to let me know about your vehicle year/make/model and the brand and model of your brake controller.

expert reply by: Adam R