Showing 12V Power On The Red Wire From Tekonsha Prodigy P3 Pigtail

Updated 10/06/2025 | Published 12/11/2019

Question:

My tekonsha p3 will not power on. On the harness that plugs into the back of it I have +12V on the red wire and Ground on the Black wire. Should the +12 and Ground be reversed?

asked by: John W

Helpful Expert Reply:

It sounds like you are hardwiring the Tekonsha Prodigy P3 Trailer Brake Controller part # 90195. The red wire should only show power at the brake controller when the brake pedal is depressed. It should be connected to the stop light wire on above the brake pedal that only shows power when the brake is depressed. If it is showing power when the brake pedal is not depressed than it is not connected to the correct wire at the brake pedal.

The 12V should be showing on the black wire which is connected to the positive side of the battery via a circuit breaker. The white is the ground which should not show power if grounded to the negative side of the vehicle's battery. I have attached a diagram to help to install the brake controller. You may consider using a plug and play adapter if there is one available to bypass the hard wiring. If you let me know your year make and model I am happy to see if there is one available.

expert reply by: Heather A