AC Stopped Without Any Warning

I have a `97 Cavalier RS that was parked for several days while I was on vacation driving a rental car. All was fine before the vacation but when I returned, the AC was not working. The AC compressor clutch doesn't seem to be engaging when I turn on the AC (MAX), or when I click the AC button while on vent, or when I turn the dial on defrost. The blower works great but only blows hot air, (and YES I have the dial turned to cold and not hot).

I checked the inside dash panel fuse and it was fine (10amp). I also checked under the hood near the battery where the additional fuses are located, and that 10amp fuse was fine. The AC relay located in that same enclosure is ok as well. The guy at the parts store was nice enough to let me plug the new one in before I spent the $20 on a new one.

Just as a side note, I had a problem about a year ago with the fan resistor but I don't think it's related in any way to this issue. The Post can be found on this forum at http://www.automotiveforums.com/vbulletin/showthread.php?t=440540

Anyone have any ideas? Thanks in advance.