I think this went to a power brake for trailer but not sure. Anyone have an idea? The previous owner had a gooseneck hitch in the bed of the truck when i got it. If it is to a power brake, anyone know what make uses this plug? Last pic is the holes that I found that leads me to think it was a power brake there. Any info would be appreciated. It's a 2002 KR SCrew.

 

Looks like what you have in the pic is the factory end. Most major brand controllers will include or offer the correct pigtail that will clip into the factory ford end, and I'm pretty sure thats it. The newer trucks (mine is an 05) that clip is mounted solid under the dash.

 

i also have a couple of connectors like that in that place not connected to anything... they must be for some optional stuff or things that come in another model

 

I always thought that was an auxiliary port of some sort. seems like trailer brakes could've been hooked up though