Automatic Climate control A/C turns on automatically in cold weather. Why?

My truck has auto climate control and I typically leave it around 68 to 70 but sometimes when I turn the truck on it turns the a/c on as well. This is in cold weather where it would seem counter productive. Does anyone know why it does this. I can turn the heat all the way to high and it will not shut off unless I manually hit the the a/c button to turn it off. Not a big deal but was just curious why the truck does this? Is it to run the a/c every now and then so it does not sit unused for long periods of time? Should I leave it on until it turns off? Will it turn off if I leave it? Just curious if anyone else has noticed

Thanks!

 

Is it when you turn on the windscreen defrost? Cause the A/C helps to dehumidify the air.

 

Nope. It's when Auto is engaged.

 

I used to have an Acura that did the same thing to control humidity. I didn't realize Toyota was doing the same thing... I bet it talks about it in your manual

 

I have a feeling it is to control the humidity but I'm not sure. I feel like leaving it on with heat is bad but maybe it is the system just working how it's supposed to. It just happens today. Drove the kids to the babysitter approx 15ish miles away. System on auto no a/c on. Jumped in the truck for the ride home and sure enough the a/c is on now. Strange. I think I will leave it for instead of turning it off like I normally do. We will see if it stays on or if it will turn off by itself...

 

Controlling the humidity is exactly what it is for. If you live in a higher humidity climate and leave it alone, you will definitely notice less condensation buildup during the colder months inside your truck.
Wish I would have had this feature during those make-out sessions on lookout point back in the day! Would have had a lot less fogging going on inside the car!!! LOL!

 

Thanks for the confirmation. I personally liked the privacy the condensation brought... lol