Trailer Brake Controller Causes Brake Lights on 1994 Chevy Truck to Come On with Truck Off
Question:
1994 Chevy 1500. Came out side and my brake lights were on. Pressed the button on the controller and they turn off. Came back out 15 min later they were on again. Had to disconnect the power to the controller to keep them from coming on. When in use the controller works fine. Is it possible that there is a problem with the controller? I checked all the wiring per installation instructs and am unable to find any short. Any ideas?
asked by: Danny H
Expert Reply:
If you disconnect the red wire from where it is connected to the truck and the problem stops then that indicates a problem along that red wire. The red wire tells the brake controller you are stepping on the brakes but when you use the manual override without the brake pedal it sends voltage on the red wire to light up the brake lights on the truck.
If there is a short inside the brake controller that could be why this is happening. You would have to replace the brake controller in that case. It could also just be dirty contacts inside the controller. What you can do is fully apply the manual override and then let it snap back into place. Do this several times to clean the contacts inside.
You will also want to make sure the controller is mounted within the range specified in the instructions if it is a proportional controller.
If it happens with a trailer connected then disconnect the trailer and see if the problem continues. If it does not continue then there is likely a short on the trailer, possibly caused by a dirty or corroded trailer connector. make sure the truck and vehicle side connectors are clean and free of corrosion inside and out. Also make sure the wiring to the brake magnets on the trailer are not pinched or frayed.
I have included a couple of links on testing and troubleshooting brake controllers for you as well.
