Troubleshooting Open Ground Error Code on Tekonsha P3 Brake Controller

Updated 12/23/2024 | Published 01/13/2019

Question:

I installed the Tekonsha P3 brake controller about a year about and have had no problems until now. I recently got in to move the my truck and trailer and had the open ground error message. The weird thing is that when i push the brake pedal this message goes away and the trailer brakes work but as soon as I take my foot off the message comes back. I have checked the ground wire from the controller to the battery. The wire is run directly to the engine block to the same terminal as the battery and also checked to ensure there was no resistance in the wire. Is there anything else I should check or does it sound like my brake controller is toast?

asked by: Brad

Expert Reply:

The owner's manual for the Tekonsha Prodigy P3 # 90195 states 4 possible causes of a "NO Trailer Connection!" warning: the trailer is not connected to the tow vehicle, the trailer is connected with an open circuit on the brake line, the trailer connector came disconnected or is corroded, or the trailer brake magnet has a bad ground. First thing I would try is unplugging the controller for several seconds to allow it to reset.

You will want to ensure that all the wires are secure at their pins on the inside of the connector. If you have not replaced the trailer end connector, you will want to check the connections in that connector as well.

If the connectors aren't the issue, I recommend checking the trailer brake magnet's ground wire for any tears or damages. If each of the brake magnets are grounded to the frame, I recommend running them to the main trailer ground.

expert reply by: Jameson C

Renat Z.

12/21/2024

Jameson C you have not answered to the questions, and I have the same issue as Brad have. The error is “open ground no brakes” but you aswered about “no trailer connection” Thanks.

Jameson C.

12/23/2024

@RenatZ Sorry about that! This question is several years old so I am not totally sure why I missed that but the open ground issue with the P3 means the white wire of the controller is loose or not secured well to a ground/the battery. I'd check the connection of the white wire to your vehicle and I bet you'll find your problem.