I have installed a brake controller to the pre-installed plug under my dash. My problem is that at the back of the truck I only have the four wire connector and no brake controller wire or aux power(for battery charging) at the back of the truck.

Where are these wires located to be run to the back of the truck?

 

They are there....since 1997 in all full size trucks.

Follow that 4 pin up to next to the spare tire where it plugs into the main truck wire harness. There will be either another dead ended plug with 3-4 more wires or there will be one large plug with all the wires.

The wire will be a slightly larger diameter for brakes and blue in color. The aux charge line will be larger as well and orange in color. The smaller brown with a green trace is for reverse lights.

 

plug was completly hidden by the spare, had another person tell me to lower the spare and look - guess what, there it was. I still don't understand why stop there, just run it the rest of the way. DUMB

 

Ford in it's infinite wisdom decided to use the same wire harness for each truck regardless of options ordered to reduce part numbers and costs. This allows you to be able to convert your truck which did not have the tow package to be able to tow trailers with electric brakes. So you should be thankfull, unlike a Dodge which used the wire harness that you ordered options for. So, many a 1 ton Dodge dually came without the tow package and had to be completely wired by the owner if you wanted to tow at a later date.