Hi first off let me say that if anyone here has a link that can answer all of my questions and save server space please post it.
I have a 91 RS. power nothing. I would like to add p/w, p/l, p/mirrors along with a p/seat. however I don't know if the wiring that already exists in the car will allow me to just connect right up to the harness or If I will have to specially wire it. I know in older GM's it was cheaper for them to produce one type of loop. In other words, if you didn't have cruise control, you could just throw in the proper components and plug right in because even though the factory did'nt put the cruise on that particular car, it still received a wiring loom that would accept it. I don't know if this still holds true or not

 

No links that I am aware of and not sure what you consider old but I know my 82 FB was wired for only what was in the car. If you want to switch to power acc. then find a F body in a junk yard and remove the harness needed take picts and notes for future referance. Locks and windows are not to bad but the seat is quiet a under taking. The locks and windows will require the dash to come out of the car as the cross body harness travels at the base of the windshield just below the dash frame. It is not a easy job but can be done in a day or two. Good luck if you decide to go through with it.

 

so i see. I went to the bone yard and found a car that had all the power acc. and the wiring was different. this would mean pulling the whole loom. I did look in the wiring schematics and first thing is first. Do I have a window fuse in my fuse block. If not, then I'll have to pull down the fuse block, designate an empty space in the block, and run the wires into that space. the wiring looks simple enough from there though. but yes the wiring loom is definately different.