Reese Brakeman Brake Controller Stops Running with Truck Running
Question:
I have just installed a reese towpower 74643 brakeman. With or without the trailer connected the controller works fine with the manual override. As for working with the brake pedal it only works sometimes. It seems to work fine if the vehicle is not running but when I start the vehicle it works for about 5 seconds and then quits. I have hooked a test light to the brake switch feed to the controller and it shows power going to the unit every time I hit the brake but the controller still will not work most of the time when the vehicle is running. I turn the vehicle off wait a few minutes and it will work again as long as I dont start the vehicle.
asked by: Wesley
Expert Reply:
I suspect that the problem is internal to the brake controller, and it needs to be replaced. There is some testing you can do to determine if the brake controller is 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.
