One wire alternator woes

Ok, I wish I could say I figured it out, but I just pulled it off this morning and re-clocked it, so I could reach the positive terminal easier with the tester. When I put it back on, it was working. Didn’t change a thing in regard to the wiring. Who knows?

I was switching to the higher amp alternator to handle an electric fan, AC, upgraded headlights and a nice radio.