Troubleshooting 4 Volts Of Constant Power Getting Sent To Trailer Brakes

Updated 08/24/2021 | Published 08/22/2021

Question:

I am getting 4Volts of power constantly to my travel trailer from my 2008 Chevy Silverado. Making towing tough. Any Ideas. All of my terminals are clean and have Electric grease on them. Possibly a ground issue? Not sure where my ground is on Truck plug.

asked by: William A

Expert Reply:

Sorry to hear about your issue!

I recommend starting by unplugging the trailer brake controller for your 2008 Chevrolet Silverado and retesting the 5 o'clock pin on your 7-way connector.

You should not have any power with the trailer brake controller installed, but if you do then it is very likely that there is corrosion inside of the trailer connectors causing power the bleed out from the 12v power pin to the brake circuit. You would need to take a good look at both the vehicle and trailer connectors and make sure there is no corrosion inside or outside.

If unplugging the controller killed the power to the brake circuit, then the issue is within the controller itself or the wiring for the controller. Plug in the controller again and cut the blue wire going to the back of it at least 6" away from the controller, and test the wire coming from the controller. If you still have 4 volts of power then check that the cold side stop light switch wire (Red controller wire) is connected to a wire that only has power when the brake pedal is pressed. If all of the wiring checks out then there is likely an internal wiring issue in the controller and it will need to be replaced.

I included a link to a helpful article on trailer wiring for you to take a look at.

expert reply by: Samuel C