Ammeter discharge with key on

Gauges draw less than an amp, I think. In any case, the gauge (temp, oil) would barely be noticable on the ammeter.

Good point about the ammeter, though. Make sure the "reading" you are "reading" is not the "natural" off center it might have when off. It's why I insist you MUST use a multimeter that is fairly accurate, at least, to see what you "really have" there