Troubleshooting Brake Controller That Displays 'Trailer Not Connected' Error Message

Updated 08/22/2016 | Published 08/19/2016

Question:

Dodge installed the brake controller under the dash panel. When I connect the plug to my truck and go to trailer tow options to program I get Brakes Not Connected Do I have to drive the truck with trailer and brake for the brakes to get connected?

asked by: Ramona

Expert Reply:

If you are getting the error message "Trailer Not Connected" when using the Prodigy P3 # 90195 trailer brake controller there are several potential causes. You should only need to have the trailer plugged in to avoid seeing this message; it should not be necessary to drive for the electrical brake circuit connection to be made.

Common causes for this message often include corrosion on the contacts in either/both the vehicle and trailer connectors; check all the pins for any signs of discoloration, especially the pin at the 5-o-clock position as shown in the linked photo. Even slight greenish or whitish discoloration can indicate corrosion that can interfere with the electrical connection between the brake controller and the trailer brake magnets.

Another potential cause is a break in the output circuit blue wire that carries the controller's output signal to the trailer. A short against the trailer frame or a broken wire can prevent completion of the output circuit.

Also a bad ground on one of the brake magnets could also prevent completing the circuit so you can check that all the bake magnets' ground wires are solidly affixed to a clean bare metal spot on the trailer.

expert reply by: Adam R