The short answer is "Try it and see"
Is it a 2 position rocker or toggle? If so then the steps switch is possible, or a patio light
3 position (Spring return to center) it might be your battery disconnect 9This it could be if 2 position too)
There are many things it might control. Here is a list of the switches in my coach just inside the door.
I have a battery disconnect, this one has a red light beside it.
I have a 3 position center off,, Up is patio, Down is patio plus work (Driver's side porch type light) this one has a white light under it.
I have compartment lights (Red light inside the switch)
Ceiling lights (2 position, not lit, this is a 3-way switch works with another elsewheer in chach)
And the step switch (light burned out I installed an indicator next to it)
Yours is likely on that list...Somewhere.
Home is where I park it!