[jdamore]

Put the car in a giant bag of rice.

Kidding aside, the worst thing you could do in energize electronics when they're wet. Water itself does no damage however, it creates little shorts and routes power to places and directions where it shouldn't go. Point is, unless its an emergency you should not power on.

You could get lucky and it will work fine once it completely dries out. Depending on the weather, could be days.