12 volt disconnect solenoid

I believe in some cases the cycle from heat to cool etc causes moist air to be drawn inside and there it condenses. I actually proved this on one of mine. After replacing it the new one was mounted inverted to the original and no more problems. I do know for a fact that some relays must not be mounted inverted under the hood of vehicles that are subject to splashing etc. I found many over the years full of water.

With that said it is probably a good idea on some models to change them out just like an oil filter on a planned schedule. Every two to three years would assure a proper operating unit.