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Discussion Starter #1
I don't know if this is a problem, but is there a way to completely turn off the AC and allow ambient air to flow into the cabin without it being conditioned in any way by the car? I have noticed recently that even if the AC light is off and I hit the round "off" switch on the fan control (with the air circulation switch switches to allow inside air to flow in, not on recirculate) the ambient air that flows in is affected by the AC settings that it was last at, even if it is off.

So, for example, if the last time I had used my car I had the heat set to 75 degrees, for the next time I take my car on the road, even if the AC light is off and the fan is set to off (so ambient air flows in), the air is still being heated by the AC system. I noticed this because if I then momentarily turn the AC on and set the temperature to 60 (the lowest it will go) then turn it back off, the air that flows in is then cool. Then if I were to do the same thing and set it to 80 degrees then turn it off the air that would flow in would be hot.

Is this normal for a car, or is there some sort of fault in my AC system that is keeping it constantly on for some reason? I was thinking that I could just turn everything off and allow ambient temperature air to flow in without the car having to run the AC heating or cooling, and am worried that this may be causing me a slight loss in fuel efficiency.

Btw, I have a 2010 GT 5 door.
 

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Peanutbutter Jelly!!!
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I have the manual controls but it is basically the same concept. As I move the dial from the bottom of the cold all the way around to the warmest setting it progressively mixes the air from outside with some going through the heater core to adjust temp. You can use the AC for heat or cold but either way the car will use the heater core (tiny radiator inside the dash) to adjust temp.

Since temps have dropped here I don't need to use the AC (unless it is humid so the windows don't fog) and i just adjust with the dial (or you would with the button). Your automatic temp just adjusts the mix with a thermostat somewhere in the airstream to constantly adjust how much fresh air and heated air are mixed together.
 

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I noticed this a while back I have the manual A/C. when i removed the HU i noticed that it moves some piping inside the car so I would guess it draws the air from various points where temp could vary. something like cool air comes in from the bumper/wheel wells and warm air comes from the engine compartment... but that's just me speculating, sounds good though
 
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