Brake Controller Reads 0.0 and Brakes Barely Work with Manual Override

Published 08/27/2015

Products Featured in This Question

Dexter Electric Trailer Brake Assembly - 12" - Left Hand - 6,000 lbs

(201)

$88.57

Hook Probe Circuit Tester

(60)

$12.27

Question:

Hello, i have a prodigy brake controller and it senses when im hooked up to a trailer or not and all light and turn signals work on trailer. Brakes on trailer have worked fine up until now. When hitting brakes controller reads 0.0 but will work barely with manual slide. Checked all fuses on tow vehicle and no blown fuses. Hooked trailer up to my neighbors truck and it does the same thing. I noticed when unplugging the trailer cord from his truck that the cord was very hot. Im guessing that its from working the brakes with the manual slide. Could it be a short on one of the brakes and that why i dont have full brakes when hitting the manual slide driving down the road?? Any help would be appreciated. Thanks!

asked by: Darren H

Expert Reply:

It does sound like there is a short somewhere. I recommend performing some tests to determine if the issue is with the brake controller, wiring/connectors, or on the trailer.

In the truck cab you will need to sever the blue wire several inches from the back of the controller. Then use a circuit tester such as # PTW2993 to test the end of the blue wire coming out of the controller. It should only have power when you apply the manual override. If it shows power at idle, then there is something wrong with the controller and it will need to be replaced.

If it tests fine, then reconnect the blue wire. Then move on to the truck side trailer connector. Many times, dirt or corrosion can cause a short in a trailer connector. Make sure the truck and the trailer side connectors are clean and free of corrosion inside and out.

You can test the brake output pin and it should only show power with the manual override. If it shows power any other time, then there is a short somewhere between the connector and the brake controller you will need to track down.

If the truck side checks out fine, then it could be the wiring to the brake magnets or the magnets themselves. Inspect the power wires to the magnets and look for pinched, frayed, or damaged wires and fix as needed. Make sure the ground wires are attached to clean and corrosion free bare metal surfaces.

You can visually inspect the magnets and if you can see the copper windings coming through the magnets will need to be replaced. To further test the magnets you can follow the help article I have linked. I have also included some help articles on testing and troubleshooting brake controllers for you.

expert reply by: Michael H