There is information in the Haynes repair books that would probably help you. The Haynes book I have shows a diagram of a 1967-1987series Chevy or GMC truck.
get a haynes repair manual from auto zone or auto parts store,about 25.00.
Buy the repairing book of Haynes.. it has everything in..
most haynes or chilton repair manuals have your basic wiring diagram,they can be purchased at just about any automotive parts store.
buy a haynes book
chiltons manual or possibly a haynes manual
Haynes Manuals have all diagrams for the ranger including the one you seek
Purchase a Haynes Manual thay is specific to your truck at a parts house or bookstore.
Pick up a Haynes repair manual. I believe it has what you're looking for.
shouldn't be a serpentine at all most 3rd gens have a 3 belt system but if it does your best bet is to pick up either a haynes manual or a chilton manual both have the diagram in it
You can buy a Haynes repair manual at just about any parts store. It may take alot of flipping pages back and forth, but it works. That is how I fixed my 87 pickup.
haynes repair book at auto parts store or get a Nissan truck service manual,check eBay .the dealer wants 75.00.
I have found that a Chilton or Haynes Auto repair manual for the year and make of the vehicle (available at your local library)are an excellent source of information. They are quite informative on most parts replacement and how to troubleshoot.