Ford Trailer Brake Controller Shows Trailer Disconnected Message on One Trailer and Not on Another

Updated 05/04/2010 | Published 05/02/2010

Question:

All the trailer lights and brakes work but the controller still gives a trailer disconnected message. Works fine on my other trailer

asked by: Travis

Expert Reply:

If the controller is working fine with one trailer and not with the other then the problem is most likely with the trailer and not the truck. I would start by checking all of the ground connections on the trailer, especially the ground at the coupler and the grounds to the trailer brake magnets. Make sure all of the ground wires are connected to clean rust and paint free metal surfaces.

If this does not solve the problem check the power feed wires going to the trailer brakes to be sure there are no bare, pinched or frayed areas that could be causing a problem.

Next, check the trailer connectors, check the inside and the connection sides for white or green corrosion that could be causing bleed over from another circuit to activate the message on your controller.

Finally, if none of the above recommendations work you may have a problem with the brake controller itself. If you have a 2005 or 2006 model Ford truck, these controllers are predisposed to problems and are usually changed out for aftermarket controllers. Once changed out, the PCM must be flashed to rid the computer of a fault code because the original controller is missing.

If you decide you need a new controller, I would recommend the Tekonsha Prodigy P2 Brake Controller # 90885 for your vehicle. This is the smoothest brake controller I have ever used and is easy to adjust. Along with the brake controller you will need a plug in harness specific to your vehicle year, make and model.

expert reply by: Robert G