Troubleshooting Brakes that are Locked Up on Trailer

Updated 11/02/2009 | Published 11/01/2009

Question:

I have a subaru forester in which I fitted a tekonsha voyager brake controller. I recently picked up my new van in Brisbane and travelled approx 600klm back home with no problems. Itook it over to Tannum Sands on the week-end with no problems going over however when I went to leave the trailer brakes have locked up and would not release. Itried adjusting them on the controller to no avail. Ialso noticed that the light on the controller did not change when I tried the adjustment. Do you know what could be the issue?

asked by: Rod C

Expert Reply:

Trailer brakes are engaged by a magnet that receives power from the brake controller. If the magnet is receiving power when the trailer is connected, and the brake pedal is not pressed on the vehicle and the power setting is adjusted properly then there is a wiring situation that needs to be rectified. I would begin by checking the brake feed wire close to the trailer brakes themselves with a circuit tester, item # PTW2993 if needed, to see if there is power going to the trailer brakes when the trailer is connected to the vehicle. If so, then there is a problem somewhere on the vehicle that is sending the power to the brakes. If there is no power on the brake feed circuit, then there is a problem with the trailer brakes themselves.

Checking the controller would be next, you should have power into the controller on the black wire and power leaving the controller on the blue wire when the brake pedal is pressed, or the manual slide knob is activated. The red wire should have power on it only when the brake pedal is pressed. The white wire needs to be connected to a solid clean ground or preferably the negative battery post.

Finally, if these functions are working correctly you will need to check the trailer connector on the vehicle and be sure it is not shorted and is wired correctly. If the brake controller is applying power on the blue wire circuit without the brake pressed or the manual slide activated, then the brake controller itself must have a problem. Brake controllers have no internal user serviceable parts.

expert reply by: Robert G