My a/c compressor is only blowing hot air when I turn it on. I know a little about cars so I know it's the a/c but I am not able to find one on any site that may sell used or new.

Assuming you hear some kind of clicking noise when you turn the AC on (the compressor clicking on):
Seals on the AC compressor likely bit the dust. GM AC compressors go out almost as frequently as tires. The good thing is that they're not horrifically difficult to replace. You can get some freon with dye in it at your local parts house. Get enough to fill it up as though it's empty (as it likely is), and see if it starts blowing cold. It should blow cold for a little while (days/weeks maybe), but when you open the hood, you'll notice some green dye around the compressor. That's where the seals have failed and why you get to be the proud new owner of a brand new compressor (don't waste your time on a used one from a salvage yard. You'll get to replace it again soon, if you do.)

with the engine off and keys in your hand,find the ac compressor and try to turn the clutch assembly in the very front of the compressor,if it is hard to turn,then the compressor is bad.

The question is: why isn't the compressor clutch turning

The compressor isn't likely seized,it may leak refrigerant,
but won't be what your asking.

The clutch can be jumped to test that

If okey, then you have to diagnose the entire
A/C Electrical System

How do you know it is properly charged,you put
refrigerant gauges on the system?

I have a Lincoln Ls 2000 v8 my A/C is not working every time i turn it on it comes out hot from both sides including the back seats do i have to change everything and buy everything new..

What do you mean when you say it wont shut off? is it blowing hot air or do you just feel a lite flow of hot air even if you have the settings to cold?

If this is the problem that you always feel hot air at low flow and the ac goes to hot air then i would say one of two things, first if you have the selector to cold and you feel hot air then there may be a problem with the blend door, this door move to allow hot or cold air, the door may be broken or just a bad motor that controls it. keep in mind if the ac system shuts down for any reason the air then will be warm, it will be about the same temp as outside and maybe a little hotter.

this problem almost sounds like the ac compressor shuts off and then you are getting the outside air which is hot, there are many reasons for the compressor to shut off, it could be the compressor clutch heating up and disengaging , this would be due to a bad compressor clutch.

another reason is the fans are not working, the best thing to do is when the system starts to blow warm check and see if the compressor is running, start engine and look at the front of compressor, with ac off the front of it will not move, and then with ac on the front will spin, check it out and let me know, if it blows warm air and ac is not working then it may be compressor problem but if you are getting warm air and the compressor is spinning then it may be a door problem.

This is hard to check with out testing the system, so i listed a few things to check and let me know the out come. also the ac blows cold for how long before it gets hot air blowing out of the vents, good day.

My 2003 Toyota Camry AC often starts blowing hot air and the AC light starts blinking. I don't know why the following process works, but it does. Using the temp selector (left) reduce the temperature all the way down to Max Cold and then push the Auto button. It will start blowing out very cold air. After a little while push the temp selector to the desired temperature.

does the air not blow when it is turned to hot or does it blow but just not hot? If it blows but not hot you need to replace your thermostat and heater core which looks like a little radiator under your dash.

Check the belt on the compressor, is it slipping on it ?

Hi, there are several reasons your vehicle may be blowing hot air through the vents, such as a need to recharge refrigerant. There could also be a problem with the air conditioner's compressor. Vents will blow hot air if the compressor does not activate when the A/C is turned on. There may be an obstruction in the system, or the blend air door inside the HVAC unit may be stuck in the HEAT position so no air goes through the A/C evaporator.

possibl ac compressor clutch problem,cooling fan at rad not working so ac goes into high press mode and turns off(so it doesn,t blow system apart,built in safety)not enough r134 in system(low charge)