Need wiring diagram help please.

My father in law is looking to buy or obtain a diagram for his FL80 series freightliner. I guess the rats have chewed some of the wires off so he doesn't know where they connect. First issue is that all the wires are yellow, so no color coding. He says they do have a number on them. He has bought 2 separate shop manuals and he says the wires that are still in tact doesn't match what his schematic shows ( apparently he has the wrong manuals)? Second issue is his trucks transmission computer has 2 connectors and the manuals show 3. His truck is a 1997 with the cat 3126 and Allison transmission. Anybody know where to get a manual or schematic for this.

 

Thanks, He has called one but they refused saying he needed to be a dealer or something of that sort. I'll try calling somewhere tomorrow and see if I can get the info. He doesn't mind buying the right book, he has just bought 2 already and they are not correct. He would like to verify the book before buying a 3rd.