04 Trailer wiring harness

[obxdivr]

I am looking for assistance with the factory wiring that came with the tow package on my 04 Expedition. Talked to the dealer today and they say that I have a light/std. tow package, ie class III/IV hitch and 4 pin plug. There is a wire for an electric brake and connector under the dash for the brake controller connection. The dealer said that everything was connected as far as under the hood. What I need to know is how do I convert the 4 pin to 7 pin and where should I get 12v power from?

 

[mustangrfast88]

i used to put trailer kits on everyday and what you have to do is buy a 7 way trailer plug kit and the dealer is right the is a plug in under the dash for a brake controller and it wires right up and as for as a 12volt source i would take it from the battery