the ammeter should have a wire directly to the batt terminal on the starter and another to the key switch, and maybe one to the light switch, which does have bimetal 'circuit breakers' for the headlight circuit - is this 'pulsing' happening with the key OFF?
if the problem started after the body shop was goofing with it, it wouldn't be a suprise if they broke a wire or left something dangling, you need to recheck every wire in every circuit .... and don't hook up the battery again until everything is back in place, use an ohm meter on suspect wires, not a smoke test
Bill
