Just noticed that when my A/C button is on or the recirculation button is activated that the engine revs oddly, but the RPM's don't change. Also when either of the two buttons are activated there seems to be a pressure release sound coming somewhere near the alternator. Any help or guidance would be great! thanks!

 

From past experience it's just the ac pump kicking on and off. When you run defrosters it will turn on to get rid of moisture in the car. And the car will bog a bit when the pump turns on

 

Is there a fix for this? Air is now not working. Makes the same sounds as before. Thanks guys.

 

Was overcharged, just released the freon with a nail. Works great now!