A/C compressor is whinning

[Campbell]

My engine is making a whinning noise from the A/C compressor. I know this because I removed the belt in the fall and it solved the problem. I'm having a new belt put on today and would like to know what to suggest to the shop. They seem to think my compressor is on the way out. It seems to work fine though. Any ideas?
Thanks

[Mike Hippert]

If it work (blows cold air), then I would think it could be the pulley or the clutch slipping. If it doesn't work (AC blows warm air) I would say you are low on refrigerant.

[Campbell]

It make the sound all the time when the belt is connected. Even when I'm not running the AC.

[Mike Hippert]

There is a red wire on top of the compressor with a connector on it. Pull this connector apart. That wire controls the clutch, it should only get 12 Volts when you turn on the AC. My clutch would sometimes engage (get 12 Volts) after going through deep water and then it would whine. IF this is your problem I would trace the red wire back and find the relay as it needs to be replaced.

[rover4x4]

cut the AC belt :evilfinge

[Campbell]

I cut it last fall and the whinning was gone. I would like to have A/C for the summer so I want to put a new belt on. Mike....Do you happen to know what the relay part number is. If it is cheap enough I may just replace it. Also are you saying if I pull the red wire out of the compressor and the whinning stops it is the relay?
Thanks

[Mike Hippert]

THe relay is just a normal relay like the headlight relay, what happened to me was 2 things, one low on refrigerant which may have caused the whining, and 2 the relay started freaking out and engaging the clutch on the compressor causing it to come on and off sporadicly. The relay should only be $5 so it is cheap and easy to try. But like I said when you pull the red wire the noise should stop, you should also hear the clutch engage and disengage

[Davis]

With the belt off, turn the pulley. If it spins freely, then the clutch is disengaged. If it spins the compressor, then your clutch is frozen. Take a look at the belt--if the sides of the belt are cracked or if there is any loose threads, then the noise may have been just the belt. If the pulley spins freely, and the belt did not make a difference, then it most likely is just the pulley bearing. take off the pulley and just replace the bearing.