I've lived in this house for 30 years. The house was built in 42.
There is a mystery light switch in my kitchen. I'm not sure what it does. I removed the cover once and the wires leading to it were kinda funny. One answer I got from an old timer was that they were low voltage wires that lead to a relay that would turn the outside light on the farm power pole on and off. That way the light did not have to be illuminated all night long wasting electricity for no reason.
I also have round shaped mark fairly high up on the kitchen wall. There is a small hole in the middle of the mark and when I look in the hole I see those funny wires again.
A old timer tells me that this was a built in clock with a timer on it that would turn on and off the house water heater at certain times of the day. That way it did not have to be on all the time wasting electricity.
Wasn't it great how out ancestors knew how to conserve things !!!
To bad we can't do something "similar" to things like that these days.