Troubleshooting Intermittent Trailer Disconnected Message with Factory Brake Controller on Ford

Question:

I drive a f350 with a 40 foot trailer and I keep getting a trailer disconnect on the dash trailer brake output keeps flashing.

asked by: Donta

Expert Reply:

There's a couple of things that could be causing the Trailer Disconnected error to keep popping up on your dash. If your lights aren't working on the trailer you will want to check both the 7-way on your F-350 and the one on your trailer to make sure there isn't corrosion or frayed wires. You can use a wire tester like item # PTW2993 to make sure you're getting power to the circuits.

If the lights on your trailer are functioning correctly then it is most likely the blue brake controller wire that runs from your truck's 7-way to your dash. You will want to start at the 7-way on your bumper and trace the blue wire as far as you can up towards the cab and look for any frayed or pinched areas that need to be fixed.

If you don't find any faults in the wiring or corrosion, I recommend plugging into another trailer if possible and seeing if you encounter the same issues. If so it's most likely the factory brake controller which will need to be serviced by a Ford dealer. If the truck works fine with another trailer then look for loose grounds on your 40' trailer around the main harness and each individual brake assembly.

expert reply by: Jerred H