Connect Trailer and Factory Brake Controller in 2005 Ford F-350 Still Shows Trailer Not Connected

Question:

This truck has the built in trailer brake systems. The system will not engage the trailer brakes and says on the dash that the trailer is unhooked? The trailer plug is plugged in and fits tight. I have tried this on both of my trailers . the lights work any advice ?

asked by: Mike

Helpful Expert Reply:

Since the factory brake controller in your 2005 Ford F-350 isn't showing the trailer connected and this is happening with both of your trailers I think that it is safe to say that the issue is on the truck side.

I would start by using a circuit tester like part # PTW2993, to test for power on the brake output circuit at the back of the truck. You'll want a helper to hold the manual override while you do the testing on the connector. If you find that there is no power, which is what I am going to assume, we can move on to the controller.

From here you will want to sever the brake output wire behind the controller, push the manual lever on the controller, and then test the wire on the controller side. If this wire has power, then there is an issue with the circuit running from the controller to the connector. In this case you have two options, trace the wire to look for damage and repair it or simply run a new wire. Most choose to just run a new wire.

If there is no current on the output wire, the controller is most likely defective and will need to be replaced. In this case I would go with the Tekonsha Prodigy P3 Trailer Brake Controller, # 90195, with Plug-In Wiring Adapter, # 3065-P. This is our best-selling brake controller because of how well it works and how easy it is to setup.

Please keep in mind that installing an aftermarket brake controller will set off a fault code on the dash. The fault code won't have any effect on the operation of the truck but if it becomes an irritation to you, a trip to your local Ford dealer can get the code removed.