It may depend on the vehicle, but on most vehicles (new ones) they are cooled seats, and they do indeed use the A/C system. Some are just better than others. For instance, the "cooled seats" in my Challenger Hellcat aren't anywhere near as good as the ones in my mom's Mazda CX-5.
I may have to try a pair of those ones you ordered. It was 118 degrees Fahrenheit today here in Arizona where I live![]()
I believe that most (all?) cooled seats use Peltier coolers, not the A/C system in the car.