Fremont Motors discusses heated seats on some American cars on a recent blog post, including when they'll turn on and how to disable the auto-on feature.
On some cars, the heated seat feature kicks in at 40 degrees Fahrenheit. Some models also offer this on the steering wheel as well. When the seat temperature goes above 80 degrees, the vented driver's seat starts to cool, thanks to perforations in the leather seat.
Heated seats are especially convenient on vehicles equipped with remote start, since the car will be nice and comfy once you get in. The Uconnect smartphone app offers remote start with an auto-on climate control feature.
If you prefer not to have the heat feature kick in on your seats automatically, go to the settings option on the vehicle's Uconnect touch screen. Scroll down to auto-on comfort and choose the option that works best for you. You can also adjust the settings for a heated steering wheel this way.