Troubleshooting Brake Controller Not Activating Trailer Brakes on RV

Expert Reply:

Since the brake controller is not powering on, I would start by checking the black wire at the back of the brake controller with a circuit tester, # BTMT15. You should have constant 12 volt power to this wire. You should also check to be sure the white wire is properly grounded to the vehicle chassis, or the negative battery terminal.

If those wires are correct, move on to the red wire. This wire should have no voltage until the brake pedal is pressed. With the brake pedal pressed it should have at least 11 volts for proper brake controller function.

If both of these circuits are functioning properly, you should have output on the blue wire when the manual override lever is activated. Check the blue wire for output when the manual override is activated. If there is no power coming out of the brake controller it may need to be replaced. If you have a newer brake controller, like the Prodigy P2, you can disconnect the power to the controller for a period of 3 to 5 minutes and allow the controller to reset. This may help, the controller to function normally again.

If you have output on the blue wire, you will need to turn your attention to the trailer connector on the vehicle and trailer. Make sure there is no corrosion in the connectors, and that the wiring inside the connectors is properly attached to the correct circuit and that the connectors are properly grounded.

If these steps do not help, let me know what you find and we will see what we can come up with. The year-make-model or your tow vehicle, make and model of the brake controller and any info on how it was installed would be helpful.

expert reply by: Bob G