Troubleshooting Trailer Brakes Not Working After Breakaway Pin Pulled

Updated 08/02/2019 | Published 08/01/2019

Question:

I hooked up to my fifth wheel at storage lot pulled ahead a little to test the brakes and everything was ok, turned out of the gate and my trailer brake away cable got pulled out and locked up the brakes, I reset it but now my brakes dont work hooked to the truck. the fuse in the truck is good. Thanks

asked by: Jack H

Expert Reply:

If the trailer brakes aren't working anymore after the breakaway pin was pulled it's possible that the brake controller on your truck was damaged during the incident. A lot of older brake controllers didn't have the circuit protection built-in to them to prevent backfeed from the trailer when something like this happens.

To test the controller you will want to sever the blue brake output wire a few inches from the back of the unit. Test the blue wire with a circuit tester or multimeter, both with the controller idle and also when applying the manual override (being sure it's set to max power). If you aren't getting power in either instance, even when applying the manual override, then the controller is damaged and needs to be replaced.

If this ends up being the case I highly recommend the Tekonsha Prodigy P2 Brake Controller # 90885, which features a nice digital display with continuous diagnostics, 3 boost levels that let you fine tune your braking, and the mentioned circuit protection to prevent this from happening again.

If the brake controller actually tested out fine then there's likely a short somewhere between the truck's 7-Way and the controller. Try and inspect the blue wire all the way down the truck and look for any pinched or exposed areas that need to be replaced.

expert reply by: Chris R