A/C is dead

I have a 2000 Zx2 Auto, I bought the car during the winter, so didn't really think to test the A/C. Now it is hotter than hell outside and the damn A/C doesn't work. I thought maybe the refridgerant was just low, but when I check the pressure it is staying between 80 - 90 PSI. When I try to turn on the air, the RPMs dip a second then come back up, sometimes the RPMs just rise a little bit without a dip at all. The air coming out isn't hot it is more like luke warm. Any ideas?

EDIT - I also put a can into the the system to make sure it wasn't just low and the compressor never kicked on.

EDIT 2 - After looking around on some other forums I found some people with the exact same problem, looks like it is ussally the CCRM, I'm going to borrow a multimeter tomorrow and test it.

80-90 psi WITH compressor running indicates a problem, blockage or something. If the compressor isn't running when you see that pressure, the refrig charge is probably pretty low, I think about 200 psi or so is typical of the system pressure when fully charged and equalized (compressor at rest). Might take more than one can to get it started. Try hosing the condenser with water while charging, helps the charge go in faster and so the compressor will start. What may be happening, if you think the compressor starts momentarily then shuts off, is when you have a low charge, the system may have just enough pressure for the compressor to start, but then right away the suction side's pressure drops to the point of low pressure cut-off, and stops again. You have to get system pressure up high enough to overcome this before the compressor will stay locked in. Sometimes that takes more than one can.

Just an update, I got the new CCRM today and put it in. A/C works like a charm, ice cold!!!