Probably. Assuming none of the control components are housed in the climate control stuff instead. I'm sure you could rig up some voltage provider, but I'm curious as to whether the 3-stage power switch on my car, for instance, just provides varied voltage to the fan, or whether it actually controls/regulates the peltier pump or other more complex stuff. The power controls are a part of the climate control unit on the dash.
Also, the support material on seats that use cooling/heating fans is different. It's a sort of spun plastic mesh that allows a lot of air to pass while still being supportive. Normal foam wouldn't work. You can sort of see it in this picture of my shredded driver seat:

You can also sort of see the flexible duct that directs air to the seatback in that picture, in the gap between the seat bottom and back.