Electric Trailer Brakes Make Noise But Will Not Engage

Updated 02/18/2015 | Published 02/17/2015

Question:

I just finished a new trailer build. Everything is brand new but the electric trailer brakes wont engage. They are Dexter brakes and I have a Tekonsha Prodigy 2 controller. I have good grounds and power everywhere it should be and when the manual lever is thrown or the brake pedal pushed...nothing. No clack or clank sound of the magnets engaging. Just a high pitched whine noise coming from the drum assembly. Any help would be greatly appreciated. Thank you.

asked by: Cody

Helpful Expert Reply:

The first thing you will want to check is the output voltage on the brake controller. If it is set too low, it will not send enough power back to engage the trailer brakes. For testing purposes, it is easiest to set it to full power.

Using a meter or circuit tester like # PTW2993 make sure that power is getting back to the trailer connector, which it does sound like it is. Then with the trailer connected make sure power is getting to the brake magnets which again it sounds like it is.

That would mean that the culprit is a ground. Brake magnets will need to be grounded near the magnet to a clean and corrosion free bare metal surface. If the trailer frame is aluminum, then ground the magnets to the axle. Make sure there are no pinched or frayed wires.

Speaking of wires, make sure that the wire gauge used is large enough. I would go with 12- or 10-gauge wire but nothing smaller than 12.

I have included a link to an article on testing brake magnets but if the brakes are new then it is not likely that they are the problem. Another thing you can do is couple the trailer to the hitch ball and if the brakes start working fine then that is an indication that the grounds on the trailer are not sufficient.

expert reply by: Michael H