Heat Uses "ac"

[SuperCoupe400]

The first time i tried using the auto climate control for heat in my '93 SC4, the AC decided to get in on the action too. Why in the world, especially in single-digit temperatures, would the AC kick in when using the auto climate control to get the cabin to 76 degrees? The only logic i could see behind it is in possibly controling the air's moisture content. Is this normal?

Can anyone enlighten me?

thanks,

Michael

[JDOwen2]

you got it. It's dehumidifying.

[lovlex]

did you have the defroster on?

[SKperformance]

All auto climate controlled cars turnt he a/c on even if it is max heat

you can turn it off if you want though but the auto light shuts off but the rest of the controls are still computer controlled

[SuperCoupe400]

Thanks for the replys. I kinda figured it was a humidity control thing. I just don't like the thought that the car may be sucking up more gas that necessary (running the ac) and the extra pull on the engine, so I usually just turn the ac off when doing "auto" climate control.

MJB

[Marty Witt]

That always made me wonder too, but the more you think about, the more sense it makes. Your supposed to run you A/C occaisionally during the winter to keep the seals lubed, so by setting it to AUTO, it does it for you. By the way, my A/C turns off after about 10/15 minutes of running.

[K9crew]

The only logic i could see behind it is in possibly controling the air's moisture content.  Is this normal?

←

Yes ... it makes sense since the water "holding" ability of air is directly related to its temperature. As air cools its ability to "hold" water decreases. That's why most a/c systems have to heat the air (slightly) after the air has been cooled but before its delivered to a room/car etc. Otherwise water would condense on numerous surfaces and we wouldn't like that very much.

:)

[Shaggz]

I tried explaining this to my wife a while back when I first bought my LS400. I think it's funny how people relate A/C so strongly with "cold air" when all A/C really means is that the Air is Conditioned in some manner, particular the moisture level.

How in the world the two ever become so synonomous??