Well what I definately know is that there are 4 pass thru wires that should be right above your master cylinder in your engine compartment that should be very visible, you can also find these pass thru wires under your dash in a bundle of capped off wires right on top of you parking brake.
Now what Im not too sure about is the wiring harness and the plug and play. From what i read last night there is a wiring harness in the engine compartment near the back but not too sure what it does. I was on the ford fleet body builder site all night and there was tons of good info and wiring diagrams, color codes, locations, good places to wire lights and what not. I just downloaded the whole book which is 390pgs but you dont have to do that there is a table of contents.
Here is the link, after reading my post i dont think i was really that helpfull but this place should be
https://www.fleet.ford.com/truckbbas...8/maintoc.html