GMC Repair: 1992 GMC Seirra A/C Compressor wont run, gmc seirra, blower works

Question
I have a 1992 GMC seirra.  When I push the A/C button on the dashboard I hear a click under the dash but the A/C compressor clutch does not engage and the compresor does not run.  How should I troubleshoot this situation and find the problem?  The air conditioning was working fine and just quit one day.  Sounds like an electrical problem to me.  The heater and blower works fine so I don't think its a fuse.  Any ideas you have would be greatly appreciated.
Thanks
Mike

Answer
The first thing to try is to check the low pressure cycling switch. It is attached to the accumulator, just unplug it and unscrew it and if everything works fine when you put it back together then you should replace it. Otherwise I would need to know what your pressure readings are to know if you have a low charge which would mean a freon leak.