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Troubleshooting a Hopkins Agility Electric Brake Controller for Locking up Trailer Brakes


I purchaced your brake controller at NAPA #755-2281 on 7/21/11 had it installed and pulled a 24ft trailer with a race car in it many times, it worked flawlessly.. I also have a smaller car/farm tractor trailer that I towed many times with no problems.. last week I hooked it up and tested it as I always do and the brakes locked up and would not release.... I pulled the trailer wheels and checked brakes every thing was good and the wheels turned freely.. I reconnected the electric brakes and the locked the brakes and would not release.... I hooked the trailer to my other truck a F250 with a different brake controller and everything worked fine.. Is there some wat I can reset the controller so it will work properly like it used to....

asked by: Paul M

Expert Reply:

Typically the problem you are describing is a short between the 12 volt power circuit and the brake output circuit at the trailer connector. Since you tried a different truck and trailer and the problem went away that leads me to believe that it would be on the truck side of the connector. I would recommend you inspect the connector on your F150 and fix any corrosion or exposed wires that you may find.

If that does not fix the problem you can cut the blue wire leaving the brake controller, leaving enough wire for you to be able to reconnect it, and then test for voltage on the controller side of the wire to see if it is always putting voltage on the circuit. If the wire only sees voltage when you slide the manual override then you know the controller is fine and that it is a short somewhere between the controller and the 7-way at the rear of your vehicle.

If it is always seeing 12 volts then either the controller is bad or the stoplight circuit (red wire) of the controller is not correct. This circuit should only see voltage when the brakes on your vehicle are applied. You might try using a circuit tester like our # 3808 to determine if this circuit is working correctly.

expert reply by: Jameson C

Jameson C

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