98 lumina, 3.1
about 265,000 miles.
vent motor has been changed about 75000 miles ago(??)
I have the usual vacuum reservoir problem.but if I play with the speed switch, etc. usually it blows out the correct vents.
question= sometimes the fan volicity seems weak, then later much stronger.
is it possible that,s a sign of a resistor malfunction? or just the motor going bad ?
thanks for any advice