Troubleshooting Trailer Brakes that Lock Up After 7-Way Install

Question:

Hello, I just purchased from your the 7-pin connector for my 2007 Nissan Frontier. My truck already has the tow package and it previously had a 4-pin connector. I connected the 7-pin connector underneath and near the spare tire and lights work. However, the blue and white wire in the connector which are for the trailer brake is always at 12 volts even when the car is in neutral and no parking brake. As a consequence is trailer brake remains engaged, even when driving. I have ruled out a short in the trailer because if I feed the pins on the trailer side with 12v then the brake engages, else it does not. suggestions?

asked by: Daniel G

Expert Reply:

Sounds like you somehow have the 12 volt accessory circuit shorted out or miswired to the brake output circuit. Does the 1:00 pin of the 7-way have voltage all the time too? If so then it has to be a short, if not that would mean the circuits were wired backwards and you could just swap the wires that feed the 1:00 and 5:00 positions and that would take care of the problem.

expert reply by: Jameson C