Ford Alternator Wiring

A friend of mine just purchased a ford p/u, I beleive it's an '84. I told him the alternator is not charging, because voltage across the battery is 12.5 somtimes it jumps to 12.7. O know it should normaly be 13.2 - 14.2. The stator wire is unhooked and taped to the pos. bat. cable. I'm pretty sure this wire should tie in somewhere but I can't remember where. Does anyone know? Also when you unhook the regulator harness on an external regulator, if you jumper A-F terminals it bypasses regulated voltage and full fields the alternator, but on this one if you jumper those two terminals it burns the jumper.