Troubleshooting Trailer Wiring Where Brake Output Circuit is Hot all of the Time  

Question:

Helpful Expert Reply:

The brake output pin of your 7-way (5:00 position) should not have voltage on it all the time. The only circuit that should have voltage all the time is the 12 volt accessory circuit which is in the 1:00 position.

You'd need to look for a short on the brake output circuit wiring before it gets to the connector and fix as needed. Or if the controller is putting out 12 volts all the time the issue could be it as well.

Testing the brake controller is fairly easy. Sever the blue brake output wire near the brake controller leaving enough room to reconnect it and then apply the manual slide. Using a circuit tester like part # PTW2993, you should get output to the controller side of the wire you severed. If the manual slide activates the trailer brake output wire properly, try the brake pedal. If the brake pedal activates the brake output properly also then the problem is farther back either in the vehicle wiring or on the trailer.

If either the brake pedal or the manual slide are not functioning properly you will need to test the wires going into the brake controller. Make sure you have power entering the brake controller on the black wire. On the red wire you will only want power when the brake pedal is pressed.

If there is power on the red wire before the brake pedal is pressed you have connected the red wire from the brake controller to the wrong circuit. You would then need to find the brake switch wire that has power ONLY when the brake pedal is activated.

If these connections check out and the brake controller is properly grounded then there is possibly a problem inside the brake controller.

I am including a link to a video that will show you how to test the wiring on a brake controller.

expert reply by: Jameson C

1

click to enlarge