ive noticed now that its gotten cold in NJ, when i have the heat on, for ex, set to 80, once the car reaches that temp, i feel the ac compressor kick in, im guessing to cool the air down, to maintain the temp, but with the outside temp at 45 degrees, shouldnt it just mix the warm air with outside air to cool it down, and not have to turn the ac compressor on to cool down the air?

 

it is to cool the car down, or regulate int. temps. it comes on with the defrost or if you just let the car control the temps. just hit the a/c button and the "a/c off" prompt should pop up. it should not come on then.

 

Well, it does it when the climate control is in auto, i dont see why the ac compressor should turn on when the temp outside is 40 degrees

 

it does it to condition the air in a sense. kinda stupid imo. either remove the ac belt for the cold months or simply turn the ac button off after you hit auto. it will still continue to run in auto mode even though the light isnt lit.

 

the ac is running when you run auto or def to help remove humidity from the air. it helps with defogging the windows quicker

 

I noticed that too. Had AC running all the time in cold weather and didn't even know it until a while later.

 

you can gain 2 - 4 mpg by AC leaving off... just activate when you need to clear the windshield

 

not to mention the drain on the engine, and loss of gas mileage

 

whenever u have it on Auto, the AC is on. i think it does that so that u wont feel so stuffy and wont fog up the windows.