So, here's another curious question. I set my temperature at 78 because it's cold outside and turn on the Auto on the dash. My AC light comes on. I can understand if I'm looking for cold but I'm looking for heat. It doesn't turn on anything cold but it just lights up. I manually shut it off and it's fine but why is it on at all? Any thoughts?

 

The A/C also dries the air, in cold weather dry air is better, prevents misting / fogging up of the windows, so the A/C is programmed to come on regardless of the set tempertaure. If you set it to demist it will be on permanently, you can't turn it off.