There is a rocker switch that is a momentary switch that is marked (Aux LP ) it is located on dash under light switch next to ether switch and mirror heat switch , what does this switch do?
Should be the one that turns on the driving or fog lights.
Would like to see a picture. You should also review the wiring diagrams. Sounds more to me like aux lp to the engine for added power. Does the switch match other switches? Coaches can be radically different even within the same year due to original owner specifications. Add in 15 years of various owner upgrades with or without the factory's assistance and its tough to say definitively what something is. My coach was ordered with oak floors front to back, overhead cabinets deleted and factory installed 110V heat tape on all water piping. There are additional outlets installed to power the heat tape system and none of that is shown in the wiring, but it is indicated right on the build sheet.
On my 99 I have to have the lights on and I think the ignition for the fog light switch to work. Try that and see.