Actually, on our trucks (maybe all newer vehicles?) the A/C works whenever the defrost is turned on - so, if you clear the inside of the windshield and defrost it in the winter you are using your A/C.

I could be wrong about this becasue I very rarely have to defrost a windshield but it seems like I remember the compressor cycling even withthe heat on defrost.

 

Yes they do run when your defrost. But how many peaple know that.
Whats your 20 redtramic?

 

A/C on in defrost is a real drag when it's minus 10 degrees, easy to overcome though
click this- http://dodgeram.org/tech/repair/HVAC/Defrost_AC.htm

 

I thought I had seen that somewhere - not that I need it where I live. If it ever gets to -10* around here then I am moving south as soon as it thaws out

 

This state has never seen -10 or -20*.Defrost issue isn't a problem here.

 

Joking, the A/C on while on defrost does do some good down here in the humid south. If you ever leave your windows cracked overnight in high humidity and the get in your truck early on a cool morning, you will find condensation form on the inside of the windows. The compressor running actually aids in excess humidity removal at a rapid rate when the defroster is on. Same issue holds true if you drive thru, window down, a steamy area after a rain while your A/C is on and inside of truck is cold. Condensation forms on the cold inside surfaces and again, the A/C running turns into a big de-humidifying unit. Psychometrics at their best!!!!!

Gary