93 90CS A/C intermittant operation

[Elliott Potter <epotter@abraxis.com>]

Well, I thought it had gone away but it hadn't.

The A/C compressor in my 93 90CS doesn't seem to work all the time. 
Usually if the car has been sitting out in the hot sun for a while (go
figure), the compressor will not turn on.  Period.  You hit "Auto" which
should turn it on, and nothing happens.  (Though the fan blower works
fine).  If you hold down the A/C button, the little "snowflake" icon
comes up, but the compressor doesn't kick in, and the icon goes away
when you let go of the button.  So far, I have replaced the compressor,
compressor clutch, relay controlling the compressor, A/C head unit,
full-throttle sensor, exterior ambient temp. sensor, and a few other
things that are escaping me at the moment.  The compressor will usually
kick in by itself about 2 or 3 minutes before I get where I'm going (no
matter how far it is or how long it takes) and seems to be totally
unaffected by speed, bumps, steering, braking, or anything else.

Any ideas?  I'm out...

Elliott