bigblue95z

If you've got the temp selector on cold, and the climate control set to defrost/floor, defrost, A/c, and Max, the A/c compressor is commanded on. If you turn it to hot, does it blow hot air? Its purpose is to pull moisture out of the air/off the windshield. If you're blowing air at something that has the same humidity, you won't remove the condensation. You can listen for the a/c compressor clutch to engage/disengage. Should be about every 5-15 seconds you'll hear a clicking sound and will usually change the engine idle a little when it come on/off.

GreyStang

Yeah if I crank the temp dial to HOT then the incoming air does get "much warmer". But I've had this car for many years, and I can tell the "hot" isn't quite as hot as it used to be. It's like the hot is blending with the AC cold and the result is kinda luke-warm. I think you're right the AC should just be cycling on/off when in defrost mode to take away some moisture. But in my case it the AC is staying ON all the time.
I wonder, where is the switch/relay that controls the AC cycling?