ok my nieghbor has a blazer and when ever he turns on his AC at full blast his volt meter readin slowly goes lower and lower, also while the voltage is dropin the altenator gets hot. what could the problem be a short some where or could it be more mechanical.
later
"Z"

well turning on the AC you put a larger load on the car, hence the alternator working harder to keep the car running and battery charged.

The alternator might be on its last legs but it is normal for the car to have to work harder when the AC is on

my nieghbor said this is his third altenator. all three did the same thing
later
"Z"