Anything of that vintage most likely is NOT pre-wired. My 2002 Monaco Windsor was not. I did ALL of the wiring myself once I knew what I was dealing with for wires.
I installed a Bargman 7-Way receptacle on the rear of the coach. I had a 6-Way one already for my car. Wiring diagram below.
The 7-Way required a 5 wire to 4 Wire converter like this one.
Trailer Light Converter Unused Converts 5 Wires to 4 Wires | eBay
I then installed the Prodigy P-2 Electric Brake Controller and ran the BLUE hot wire to the rear of the coach from underneath installing it into a flexible plastic wire loom.
I picked up the service brake signal from my Front Run Bay electrical compartment under the drivers window along with the positive and negative wires I needed to power the Prodigy.
The BLUE wire was the only one I had to fish from the front to the rear of the coach.
Dr4Film ----- Richard