65 Valiant charging system problems after repaint (Not a grounding issue)

Litz said

Engine off, headlights on high beam and radio, etc on and the needle doesn't budge. The wiring is original and hasn't been hacked like some.

Click to expand...

i agree something is not right with the wiring now.
With engine off, any one of those items on, even the dome light, and the ammeter should show battery discharge if the light goes on.