what does it turn on?

[abcwarbot]

I have a f1850 5th wheel. you enter the door, and there is 2 switches, to the left, One I know is the outside light. But the other hummed, but we didn't see anything. So we quickly turned it off What does it turn on?

 

[Sunline Fan]

Should be the water pump switch. Good move turning it off right away, because it shouldn't be run long when completely dry.

 

[abcwarbot]

Found the pump. It's been winterized. Thanks