[lunarhighway]

i'm thinking of going for a window locking motor (couple of bucks on ebay)
that's tied to the fan when the fan comes on the shutters open, when it goes of the shutters close. from previous experiments with solid blocks i've gathered that even with an almost full block the fan only comes on when the cars in stop go traffic on a hot day, and under this condition the fan would come on at some point anyway.