[patrickt]

It's hard for me to tell why you have the readings you do. But what I can tell you is the traditional and correct way that a voltage regulator with a charging light is wired. If you take that same voltage regulator and decide you didn't want to use the charging light, or it was in a car without a charging light, the wiring to the voltage regulator would be slightly different. It's important to know both of the wiring methods just so you can spot any mistakes. It's also not uncommon for a voltage regulator to be bad right out of the box. So if you confirm your wiring connections as being correct, and you still have bizarre behavior, a bad voltage regulator could be the cause. Here are the two basic wiring schemes for your I, A, S, F voltage regulator:

With a charging light:

I on the VR connects to the charging light (the other connection on the light goes to a switched positive source)

A on the VR connects to a switched positive source

S on the VR connects to the STATOR terminal on the alternator

F on the VR connects to the FIELD terminal on the alternator


Without a charging light:

I on the VR is not connected to anything

A on the VR connects to a switched positive source

S on the VR connects to a switched positive source

F on the VR connects to the FIELD terminal on the alternator

If you disconnect your alternator leads, and your VR leads, and confirm that your switched positive sources are being applied properly, then your charging light should not be coming on. Double check, then triple check. Only then consider the possibility that the VR might be faulty.