On my '98 Coachmen, an identical switch is used to control the power step by the door. It's a simpel reversing switch, wired from the DC distribuiton system (a little bus bar in this case connected to the battery, with a few little cube circuit breakers for various things). The wires from the battery and ground would go to the middle two terminals; the wires to the step motor to the two end terminals. If the switch operates "backwards" in that pressing it in the direction that would seem to make the step retract extends it and vice-versa, flip-flop either the two battery or the two motor leads.
This is unrelated to the generator.