I have mostly identified what the various switches and gauges are and do on my "new" motorhome, a 2003 Dutchmen Express 21. Though I have a manual, it doesn't help me with one particular switch.
The switch is one of a cluster of three switches on the left of the center aisle, amidships. (The other two are: the gas furnace on/off; and the generator on/off.) The switch I need help on is a simple on/off switch with a telltale red light to show when it's on.
These are among the things the switch does NOT control: refrigerator on/off or power source; water pump; 12volt power on/off; cabin lights; air conditioner; the invertor/convertor; outside lights; the warning buzzers for gas, etc.; or anything that connects the house battery to the vehicle battery. But, then, I can be wrong!
I have a Four Winds manual that just does not address this.
I will add a picture of this panel as soon as I learn how. The mystery switch is the one on the left.