Troubleshooting a Brake Controller that Won't Activate Unless Manual Override Lever is Applied

Question:

2000 navistar 4700 brake controller works from manual control but not from brake pedal. Power from brake light switch is connected to red wire and working but no power is getting out of controller to the blue wire. Has controller failed or have I missed something? Power supply and ground are both good.

asked by: Steve

Helpful Expert Reply:

If you tested the stoplight switch wire for your brake controller and it is receiving 12 volts when the brakes are applied and none when released and still your brake controller isn't sending power to the brakes unless the override lever is activated then yes, the controller is bad.

I attached an FAQ article and video on testing brake controllers that you might find interesting as well.

For a brake controller to replace what you have 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.

expert reply by: Jameson C