belts behaving badly

91 chevy cavalier z24 3.1L auto

my speedometer goes out whenever it gets wet. eventually it dries out and works fine until its wet again.

what controls the speedometer. is it electronic or a cable, a speed sensor, wheres it located? what else could be wrong?

any suggestions? i need to correct this.

I'm not really sure, but it sounds electronic if water is making it quit.

it's always connected to the transmission.