Glenn I see why this is haunting you, with all the work you have done on this & it's still acting up, this is the charging system from hell but we're going to get it He did not mean stab into the plastic on the back of the VR, stab the probe into the wire RIGHT AT THE VR to penetrate the insulation. The ign sw(or the bulkhead) is looking like a likely culprit. OK lets do this. (1)A short jumper wire with 2 alligator clips from the alt batt terminal several inches to the alt field terminal w the blue lead. (2) a longer jumper wire w 2 alligator clips from the same alt batt stud over to the blue lead right at the VR, either bare the blue wire & clip it with the alligator end or use a metal probe on that end instead of the alligator clip & stab it into the blue wire to make continuity.