Troubleshooting Brake Controller Wiring On 2003 Ford F-250

Question:

I have a 2003 f250. I checked the wires and you had said I should only have power to the blue wire if the controller is activated but I have power there even without activating it. Should I also be hooked up to a trailer to test it?

asked by: Jason

Expert Reply:

You should not show power to the brake output wire unless the brake controller is sending it. You may have something wired incorrectly at the 7-Way. You want to make sure your connector is wired the same as the attached photo of a 7-way connector.

If not, then you want to change the wiring and place the wires in the right order. You can also check to see if any of the wires are touching each other inside the 7-Way. Check for corrosion or dirt and clean it up as that can cause shorts as well.

If everything checks out then you want to make sure the brake controller white wire is grounded to the negative battery terminal. Make sure the black wire is attached to the positive battery terminal via a 20 or 40 amp circuit breaker, and the red wire is attached to the cold side of stop light switch. This would only show power when the brake pedal is pressed. If the red wire is attached to a wire that has power all the time it will cause the blue wire to show power all the time also.Then make sure the blue wire is attached to the 7-way connector on the back of your vehicle.

I have attached some links to helpful articles you can check out.

expert reply by: Jeffrey L