Re: Thermostat
I merged your prior thread with the most current.
All of the reply's are right on, it's a thermostat for a roof mounted vent fan.
Turn the thermostat up just a bit and the fan should open.
It is designed so that you can have the vent fan open automatically. An example would be if you are going to be out on a day when it is predicted to be pretty hot then you could set that thermostat at, say 90°. When the interior of the coach reaches 90° the fan will, or should, open.
These vents require some minor maintenance such as lubricating the rubber gasket that seal the cover to the unit. Silicon works well.
On edit, can you just contact the previous owner and ask?
Peace
Dave