Why Would Tekonsha P3 Brake Controller Only Turn On With Brake Pedal

Question:

I installed my P3 when it first arrived with no problems. After using it for a few months I decided to utilize the space under the radio to give the controller. Had to splice in the longer connector wire to reach the space. Now the P3 only comes on when the brakes are applied. I have checked all the wires for continuity and they all check out fine.

asked by: Nathan

Expert Reply:

Sounds like the red wire and the black wire got switched somehow when you rewired it. The red wire normally only sees voltage when the brakes are applied and if that circuit on your vehicle is instead ran to the black wire of the controller it will only power on the controller when the brakes are hit.

expert reply by: Jameson C