My A/C and the symphony of shrieking

Hi All,

I drive a 2011, its the 1GR-FE engine, 6 cylinder 4.0 liter.

When I turn on the A/C (press the button) or turn on defrost (either of the two options for the vent switch that are directing air to the windshield) I get a screeching sound that sounds like a symphony of 1000 demonic balloons slowly having their air let out at once. Or kinda like if you've ever put a blade of grass between your thumbs and blown hard, but about 10x louder.

I may be exaggerating a bit, but truly its loud. Screechy.

RPMs don't seem to change it, doesn't stop after about 30 sec of letting my car hit the high note in 'Take on Me'.

I took a look at the belt but I'm not sure what to look for, it feels taught (I don't have any bar to compare that to though) and doesn't look worn at all, at least compared to the pictures I've looked up of worn belts.

So I'm assuming there are 3 options...
1. Belts fucky
2. Clutch is fucky or got some invaders in the bearings
3. Whole compressor is kaput

How I determine what my problem is so I can stumble through fixing it via youtube videos? Anyone else run into this?

Do I run with the ac on and see if it still blows cold air, even while screeching? Would that absolve the compressor of any potential liability? (whichever part is culpable will be prosecuted to the fullest extent of the law).

 

Look at the clutch and see if it's even turning. If the compressor is frozen the belt will be just forcing it's way across the pulley. And it will burn itself in two.

Reason it happens when you select defrost is that engages the compressor just like the AC selection does.