normally it is dead center of the guage but with the blower motor on it drops some each speed and drops some more with the lights on and will jiggle back and forth with the turn signal on. Everything else seems fine - lights do not go dim, car starts fine every time, trunk mounted battery shows good charge when checked with meter etc... This is a 1996 Ford Windstar 130?amp alternator with internal regulator on a 5.0FI - would this cause the guage to read like that? I have driven 70's before with regulators and the guage is always in the middle or a little above - I always thought that if it drops below the dead center it is discharging - is that not true? Is it ok as long as it is somewhere in the middle?