<VV> GEn/FAN Light On with Key Off

[William Hershkowitz]

                                                                                  B"H
Hi folks...have a strange situation and perhaps someone can shed some light on where the problem might be...
On my 1966 Monza, I replaced a bad "GM 1-wire alternator" which wasn't charging, with a "new" one from Clark's.  With the old "1 wire" alternator, the dash GEN/FAN light worked correctly.  When I installed the "new" rebuilt one, the light came on brightly with the key off.  I assumed it was a bad internal regulator, and Clark's sent a replacement.  Same problem, the light comes on with full brightness with the key off.  
In addition, my aftermarket voltmeter (connected to 12 volts at the fuse panel) vibrates at 11 volts.
When I turn the key to ON, the GEN/FAN light goes off, voltage goes up to 14.7 volts which is perfectly normal. The voltmeter then registers normally.  This status is the same with the engine running, the GEN/FAN light is off and the voltmeter registers normal voltage.
I need to explain what I know about this "1-wire" alternator and the charging system, so you know "what I already know."
Actually, it's a 3 wire alternator.  The big red wire goes to the battery, but there are 2 additional wires that, with the factory setup, go to the mechanical regulator.  These correspond to Terminals "R" (blue) and "2" (white).  When you wire the alternator (which has an internal regulator), you get a jumper that connects terminal "R" to terminal "3" and "2" to "4."
By removing the jumper plug, the GEN/FAN does not light up with the key off.
I know that Terminal 4 (brown) is connected to the dash GEN/FAN light.  Here are voltage tests I ran:
TERMINAL (at factory harness)     KEY OFF     KEY ON    ENGINE RUNNING
R   To Alternator (blue)                     12V           12V               12V2   To Alternator (white)                    12V           12V              12V3   To battery (red)                            12V           12V              12V4   To dash (bulb)                              0V            12V              12V
What I think is part of the problem, is the presence of 12 Volts at Terminal 2 with the key OFF.  The jumper connects that with terminal 4, to the light.  Therefore it would seem to me that Terminal 2 should have 0 volts with the key off?

The complication is, that if it's a bad regulator, why would 2 new regulators have the same issue, when the old regulator controlled the dash light normally?
I disconnect ALL my accessory (aftermarket) wiring just to eliminate anything I may have goofed, but there's the same result.
In the meantime, the only indications I have for a broken fan belt are my voltmeter (which works fine with the engine running) and my oil temperature gauge, which, if registering above around 260 degrees. might indicate a fan belt issue (in combination with low voltage).
Any help you folks can give me would be greatly appreciated!
Thanks...Bill Hershkowitz  66 Monza Sport Sedan 110/PG