Battery Symbol Light Intermittent on and off

2003 Pontiac Montana

So I got a phone call from the wife and she tells me when she is driving, the Battery Symbol Light in the dash is lit up only when the Blower is on, but goes out when the Blower is off.

Also, when the vehicle is in Park and idling, the Battery Symbol Light is on but if the engine is revved up, the Battery Symbol light is not lit.

This would lead me to believe it may be a weak tension on the serpentine belt.

I will check both the tension on the belt and the voltage level tonight when she gets home from work, but I am puzzled, because my experience with alternator is either dead or alive. Not just a little dead.

Thought I would ask if a weak (low output) alternator is possible, as I have never really had that happen before.

tia
Zig

.... false alarm.....she just got home and I checked directly at the output of the alternator and there is no voltage > 12 volts coming out of the alternator when the vehicle is running.

Time to go to the part store and get a ridiculously expensive alternator..nuts, I was hoping for a loose connection or something easy

Zig

Your problem has only begun.....wait until you try to get that sucker out....takes less than a minute on a Grand Am or Grand Prix.....in a van it is tucked in under there....