When I turn My A/C on I get a squeaking noise inside my car. All sounds good outside my car. It sounds like its coming through the vents. This only happens with the A/C on and it will stop as soon as i shut it off.

 

This happens to me too if I put the A/C full blast.

 

It sounds to me like this "squeaking noise" is coming from a problem with your A/C compressor. I assume you have no problem getting proper cold or hot air through the vents when the A/C is turned on, correct? The compressor for the A/C would need to be checked out if you have plenty of A/C refrigerant.

 

It could be the fan motor that is causing this squeaking noise. There is a button on your control panel that can manually shut off the air conditioning compressor while letting the rest of the system operate. Try doing this to see if the noise disappears. If it does, then it could be the compressor or belt that is at fault. If it doesn't, then it could be the fan motor.