Chevy Truck Fuse Block Diagrams - Chuck's Chevy Truck Pages Most recently, I picked up a GM 1982 Light Duty Truck Factory Service Manual, which includes a full wiring diagram. I won the bid for $17. Back in 1992, at a local swap meet, I paid $30 for the same GM factory Service manual for my 77. The older manuals didn't include wiring. I currently have a bid in myself on a 1977 GM Factory Wiring Manual.