fuse block

Hi people,I know that this site is for 1999 and newer,but I need some help with an older truck.A 1984 Gmc Sierra,just bought it for my son and am experiencing some electrical trouble.No power to the alternator plug in (small wire has no power,larger wire has power).Small wire tested fine to the fire wall.
What I would like is a diagram of the fuse block showing proper fuse placement (the printing is off ours). Would anyone know where I could find a diagram online?
Any help with this would be GREATLY APPECIATED

The best I can find is this: Chilton's Repair Manual
They have all the wiring diagrams for every bit of the truck

http://www.autopartswarehouse.com/performance/basket.php?makeid=10&modelid=125&year=1984&partid=91&brandid=1698