Troubleshooting Brake Controller in Vehicle that Stops Working Intermittently

Question:

I looked at this and still can't find the problem. I even cut the power wire behind the 7 pin and still no power to it. Could it be the blue power wire? Somewhere in the truck? I even tried a new harness and brake controller. Thanks

asked by: Mark A

Helpful Expert Reply:

You did an excellent job troubleshooting your brake controller issue so far. It sounds like there's a bit of corrosion on the pins of your 7-way which is preventing the controller from making a solid and consistent connection. Try taking some sandpaper to the pins of your 7-way (specifically the brake output 5:00) position and most likely will get you going.

If you find that your 7-way is corroded or damaged to the point of needing a replacement an easy solution is the part # HM40975 which will plug right in and get you going again.

expert reply by: Jameson C

Mark A.

12/10/2019

Jameson C.

12/10/2019

So we've narrowed down the problem to being further up from the 7-way connector at the rear of your truck on the brake output circuit. You can trace this wire forward to see if you can find anything that would cause the circuit to be damaged like a broken wire or a short, but if the idea of tracing factory wiring sounds daunting you can just bypass it all with a new wire ran from the blue wire of the brake controller back to the 7-way. You could use 10 gauge wire like part # 10-1-1 (sold by foot) to run from where you made the testing cut earlier back to the and you'll bypass all of the unknown issues. Routing the wire will take a bit of time but at least there's no guesswork!