Troubleshooting Brake Controller Install that Doesn't Work Unless Brake Light Circuit is Connected

Updated 08/01/2016 | Published 07/30/2016

Question:

Is there another wire that connects to the blue wire from controller to blue wire from trailer? The green light doesnt come on unless I connect it to the brake light wire,but then the light does not go out when I disconnect the trailer.

asked by: James T

Expert Reply:

Sounds like you may need to revisit all of the connections of your brake controller. The blue wire attaches to the circuit that run all the way back to the brake output circuit on the 7-way. So from brake controller all the way to the 7-way.

The red wire needs to attach to a circuit that only sees voltage when the brake are applied. So 12 volts when brakes are on and none when released.

The black wire needs to go to a 12 volt power circuit that runs to the positive side of the battery. This circuit will be hot all the time. Even with the vehicle off. This allows the controller to remember the settings you have chosen. Also, controllers don't draw hardly any power when not in use so you would not need to worry about battery drain.

The white wire goes to the negative side of your battery.

I attached a couple help articles on brake controller installs and troubleshooting for you to check out as well.

expert reply by: Jameson C