[NoD~]

Hmmm, didn't realize brushess were more efficient... Think it is possible to convert the cabin fan into a brushless? Are newer cars brushless?

As for pushing around hot air, if you have the vent open to the outside air, you should be replacing the hot air building up inside with whatever temp air from the outside. If I leave my key on and let the air circulate for a few minutes before jumping in, it's a huge difference!

Edit: I'm thinking I will just go with the PC fan route... seems easier to design. Will just simply wire it up to the full 12v system and use a circuit design that kicks them on at ~90*F+, car on or off. Seems that a pair of fans in the rear 6x9 spots won't even draw a full amp of power, where the sunroof should produce 2-5 amps in that same sunlight that would be causing the heat in the cab anyways. Thanks for your help, gang.