2003 alero a/c problem

Have a 2003 alero 4 cylinder and having trouble with the a/c. One day it was working fine and the next day it stopped working. I have checked all fuses that have to do with the ac compressor and climate control and no luck. Blower is working fine only the compressor is not engaging. Any ideas to what the problem might be would be appreciated. Thanks.

check for adequate refrigerant pressure (47+ psi)
Then check if clutch pulls in-- tap it if it doesn't- may have the classic "too wide air gap issue"

I double checked it yesterday again...but didn't check pressure. The compressor is not engaging so I disconnected the connector to compressor and connected it direct to battery and it worked. There is no power going to compressor..all fuses and relays are ok. Would the ac control panel have something to do with the problem?

Loss of refrigerant is number one cause of compressor not engaging-- I highly suggest you see if system has 47+ psi in it.....if not, you have a major leak that needs to be found and fixed. Borrow the pressure gages from Autozone to test.

You not only need gages to check what the static pressure is, hi=lo=ambient air temp, first thing in the morning before the car is started....so if the air temp is 70F, pressure should be 70 PSI.....if much lower, you have a refrigerant level problem.

If gage pressure looks ok, then you need a scan tool to read data to the PCM....this system uses a 3 wire pressure sensor(which can't be jumped like the old pressure cycling switch)......the sensor should be giving the SAME PRESSURE INFO AS THE GAGES........if it is giving too low or too high a pressure, the compressor will not run..........

System had no pressure. I put in small amount of freon and discovered the leak. It's leaking thru the low pressure valve...don't know how I can tighten it...don't wanna break the valve��