Where to find wiring diagram for my truck?

[ronniej]

i have a 71' gmc c-2500 custom camper. it has the duel battery set up and wires going back to the bed for what i asume was a in bed camper. i want to get rid of all of that and just go to a single battery and one wire alternator. i can not find wiring diagram for this wire set-up. i have a few shop manuals that have factory firing diagrams for single battery set up but none for the camper set up. does anyone know where i might be able to download a diagram for this? probably more than i can handle. i am not real comfortable with wiring.

thanks,

ronniej