Pontiac Repair: 2000 Grand Prix A/C Blower, pontiac grand prix, grand prix gt

Question
Hello Wayne!

I have a 2000 Pontiac Grand Prix GT with 88K miles to its record.  This summer, I just noticed when I turn the thermostat to 'Auto' at 60 degrees (the coldest setting) the A/C blower motor works, but I hear a very annoying humming noise I did not hear before coming from the passenger side foot well.  But when I use the manual blower setting at any level (even at the highest) the noise seems to go away.  What might cause this and should I be looking at getting a new blower motor anytime soon?  Also, I have noticed just this summer that with the A/C cranking and the car stopped - at a light, etc. - the A/C is not as cold as when the car is actually moving...any thoughts?  Thanks for all your help!

Joe

Answer
Hi, this could be the like of power coming from the auto setting, check the volts at the motor with the auto on and see what the volages is, then check it on manual, with the setting on high, there should be 12 volts at the motor.
On the low cooling this could be it's low in refrigerant.