Lots of bad solder connections (cold/cracked) in that kind of stuff. They last for a while before failing.
Try rapping on the control fairly hard with your hand or even the blunt end of a screwdriver. (seriously!)
If it starts working, you have solder issues. I good solderer can identify the cracked joints and reflow them.
FWIW, most (all I have seen) PW swtiches are totally protected from the rain. The part you touch forms a roof over the actual opening which has a curb around it. You have to take it all apart to see the construction. You can litterally pour a bucket of water over most of them and none will get inside to the actual circuitry.