Troubleshooting Trailer Brakes that Lock Up when Trailer Wiring is Connected

Updated 05/29/2018 | Published 05/25/2018

Question:

Help. 7 way connector works well except it applies brakes as soon as it is plugged in 2012 Suzuki Equator sport 4 door 4wd Curt venturer trailer brake shows single green light when brake is touched or manual slide moved, whether trailer plugged in or not. Went for test drive to check things out and brake on trailer was engaged the whole time. Unplugged 7 way harness and brakes disengaged, but I then had no signals.

asked by: Dustin

Helpful Expert Reply:

You have a short between the brake output circuit and the 12 volt accessory circuit. That's what's putting 12 volts on your trailer's brakes at all times when connected.

You'll want to go over the wiring of the trailer looking for any exposed wires touching each other or corrosion and fix as needed. It's also possible that the 7-way is incorrectly wired. I attached a picture that shows how a 7-way should be wired by function.

expert reply by: Jameson C