Troubleshooting a Brake Controller that Only Works with Manual Override Lever

Question:

My electric trailer brakes work when manually activated. However nothing works when brake pedal is depressed. Unit is not hard wired in but instead is plugged into what looks like a junction box

asked by: John E

Expert Reply:

That would indicate that the red wire (stoplight switch) of the brake controller is not correctly wired to the stoplight switch of your vehicle.

If the controller never worked properly with the brake pedal then the problem is the pin-out of the adapter used to plug the controller into the junction box of your vehicle. You will need to test the pins of the port on your vehicle to verify that they match the adapter you are using. Find the port that sees voltage only when the brakes are applied and verify that it matches the pin of the wiring harness with the red wire.

If the controller worked fine and then stopped the problem is most likely a blown CHMSL fuse. An easy way to test this is to see if the third brake light of your vehicle illuminates when you hit the brakes. If not, then that is the problem.

If everything is wired up correctly and the controller still isn't working you will need to replace the controller.

For a brake controller I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how well it works and how easy it is to setup.

I attached an FAQ on troubleshooting brake controller installs for you to check out.

expert reply by: Jameson C