I had a very old thermostat controlled attic fan. I replaced it with a new one. There was some leakage and, I believe, the new thermostat may have gotten wet (it stopped working). I fixed the leak in the roof and replaced the new thermostat with another one. That thermostat worked for about another 1-1/2 to 2 weeks, then again stopped working. Could this be from the thermostat again getting wet (it is located beside the fan opening in the roof)? I was going to try another thermostat and move it away from the fan opening.

Other suggestions?

Relocate thermostat away from opening. If fan doesn't work, bypass thermostat, and repair or replace.

Is there any evidence the second thermostat has gotten wet?