Remove green field wire at alternator. Take jumper and ground that alternator field terminal. Start and see if it charges. if not, leave jumper in place, key in "run" and chek voltage at blue wire field terminal, all wiring in place
If you have that voltage and it will not charge, rerun test and with engine running fast, check voltage at alternator output terminal. If it is still low, 12v or less, it is not charging. If it is quite high, way over 14, and not charging, you have a break in the charging line to battery
Other:
VR controls "the amount of ground" of the field via the green wire. Check wiring for function, and make absolutely certain VR is grounded.
So Vr gets switched 12V from key, as does the blue at the alternator field. The VR controls the grounding on the green thus conpleting the field and controlling it.
If it doesn't go full charge when you full field the alternator , then yeah it's toast.
If it does full charge then your regulator is bad or not grounded properly. Like he said
VR MUST be grounded.
