Automatic grill block from the factory?

[lunarhighway]

i think red's right
perhaps the temperature gauge would be a good input. on most older car i think the dials are opperated by a changeing current? so transelating this to a servo would be the simpiest way i think. all you need would be a levver that follows the path of the needle on the gauge and have it make contact with the shutters and start to push them open as the temperature rises above the nominal setting. flying model planes might supply the right technology...

[GasSavers_DaX]

I want to say that Honda or Ford played with this one time before and decided not to - maybe because if in a cold climate with snow/ice it could freeze up and then break when activated.