Trailer Brakes Stay On All the Time when Connected to a 1999 Chevy C/K 2500

Published 03/23/2018

Products Featured in This Question

Draw-Tite Activator IV Trailer Brake Controller - Up to 4 Axles - Time Delayed

(357)

$103.31

Hook Probe Circuit Tester

(60)

$12.27

Question:

Have a 1999 Chevy 2500, the 5504 Draw-tite was already in truck. Pull trailers all the time without the elec. brakes hooked up, I know stupid on my part, but hooked up to a larger travel trailer and when I hooked up the brakes, they stayed engaged without the brake pedal being depressed. Had to cut the main wire going into my plug to get them to release. What direction can I go to resolve this problem?? Thanks in advance.

asked by: Grady C

Expert Reply:

We need to figure out why the brake controller was providing constant power. If you happened to be using a 6-Way to 7-Way (or vice versa) adapter then what probably happened was the 12 volt hot lead and the brake output pin locations don't match what the trailer requires.

Otherwise it is likely a problem with the brake controller or wiring. There are some tests you can do to figure out the issue. 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