2008 Ford F-250 Will Not Start or Crank After Installing Hopkins Brake Controller

Question:

I bought an agility brake controller and #47845 wiring harness for my 2008 f-250 super duty. When I got everything hooked up my truck will not crank or start. I can unplug the brake controller and the truck will start.

asked by: Jacob B

Expert Reply:

First let's make sure you are using the proper brake controller wiring harness for your 2008 Ford F-250. For a Hopkins brake controller you should be using # HM47855. It would not hurt to make sure that it is also plugged into the correct plug on your truck. I am fairly certain there is only one though but it never hurts to make sure.

If your truck came with a brake controller pigtail from Ford and you hardwired the controller to it then the wire colors would not match up between the controller and the Ford harness. The Ford harness should be labeled and the brake controller wire functions are:

White = ground
Black = 12 volt power in
Blue = output to the trailer brakes
Red = input from the brake switch

If that is all correct, right plug, right harness, then there is likely an internal short in the brake controller and it will need to be replaced.

expert reply by: Michael H