It should send your voltage up to 17-18V (don't do it for long)
You can measure anywhere... across the battery, at the + stud of the solenoid, wherever.
This is more a test of alternator output than regulator function, but if the alternator puts out with the screw grounded and doesn't when you remove the ground, then the regulator is fried.

 

Tested that, no change while grounded. So then I changed the alt with a used unit, no change. Then I changed the reg connector and the neg battery cable...... No change. Tommorrow I'm going to the scrap yard to switch out the pos cable and fusible links.....

 

I'm sorry, I am pretty much out of ideas.
You've changed out the charge plug and checked the green/red wire for battery voltage.
When you ground the test screw you don't get 17+ volts?
You have even changed the alternator.

This is a huge WTF???

 

Do a continuity test or check with ohms the the alternator harness and check your fuseable links thier should be 3 in the harness. The ends may look all good but it may be bad on the inside and its an easy test to perform with a multimeter.

 

I know, it's driving me nuts, that and I haven't had time to really dig into it.

 

Several of us have mentioned doing a continuity test...but I don't see where anyone said to disconnect the positive battery cable 1st.

I've never tried doing this type of test on a wire with current in it...not sure I would want to

 

Actually, he says he gets 3V with the alternator connected.
I think I would start checking back towards the battery until I found 12V
Then I'd know where the problem is.

 

I had a like problem several years ago on a Bronco II. Continuity every where, no charge. The wire that went to the regulator to "excite" the alternator was down to one strand. Enough to illuminate the light, and enough to read voltage, but not enough AMPERAGE to excite the field.

 

Went to the scrap yard and picked up a harness from the solenoid to the alt. Thats all I had time for today, I will put that on tomorrow and see what I get. I know looking around the yard I found several that had seen better days, most had been repaired and some were burnt up. I will post an update.

 

Thanks for all the help up to this point!!

 

Got it!! Changed out the fusible link side and its good! Thanks for all the help!!!