Troubleshooting Tekonsha Prodigy P2 90885 Not Having Green Light and Always Powering Trailer Brakes

Question:

Hi my brake controller doesn’t show a green light when installed in my truck. I took the controller out and tested it on the truck battery and it lit up fine when I touched my tester to the blue wire. Is it possible that there is a ground problem in my truck or on my trailer? When I connect the truck to the trailer, the trailer brakes come on and the trailer won’t move. I appreciate any help. Thanks.

asked by: Steve

Expert Reply:

I would be happy to help you troubleshoot the issues you are having with your Tekonsha Prodigy P2 # 90885 installed in your truck.

First, I recommend using a circuit tester # PTW2993 to test the 5 o'clock pin of your trailers 7-way connector. If you have power on this pin without pressing the brake pedal or manual override lever of the controller, then there is an issue in the way the controller was wired.

You will want to make sure that the red wire of the controller harness is wired to the cold side of the stop light switch that only has power when the brake pedal is pressed, the black wire needs to be connected to the vehicle battery with a circuit breaker, the white wire needs to be grounded, and the blue wire needs to get connected to the brake output wire running to the 7-way.

Based on the part where you mentioned that with the truck and trailer connected the trailer brakes are always activated, it sounds like the red wire is connected to constant power and not the cold side of the stop light switch.

Let me know what you find and if needed we can go into more in depth troubleshooting steps.

I included a video of the # 90885 for you to take a look at.