Troubleshooting Tekonsha P3 Brake Controller # 90195 Reading Short to Battery No Brakes

Question:

My controller is about 4yrs old..I recently plugged it into my horse trailer and a warning no brakes red light came on, it also said short to battery. On the trailer side I have zero lights or brakes. I unplugged the cord to the trailer and the warning did not go away until some time later. Could the controller be bad?

asked by: Janaye

Expert Reply:

Since you mention that the trailer has no lights or brakes, it sounds like the ground wires on your horse trailer may be the source of the issue and not the Tekonsha Prodigy P3 Trailer Brake Controller, # 90195. It is not uncommon for it to take a bit for the display to clear once the trailer is disconnected.

Let's get the easy stuff out of the way and start by checking the connector on your tow vehicle and your horse trailer to make sure that they are both free of dirt and corrosion. Next, I would use a circuit tester like part # PTW2993 to check the connector on your vehicle to make sure that each pin has power when each light or signal is activated. When it comes to testing the brake output pin, you will need a helper to hold the manual lever on the brake controller while you test for power on the pin. If all pins function as they should, we can move on to the trailer.

On the trailer you will want to check the main ground wire to make sure that it is secured to a clean metal surface. We also recommend running a jumper wire from the brake assemblies to the main ground.

If you find that all of the above checks out to be fine and you still have no lights or brakes on your horse trailer, please feel free to email me and I will be happy to provide you with additional suggestions to try and locate the issue.

expert reply by: Leah S