"Jor2".....It may more than likely be a bad switch, but the Onans also have issues with water occasionally getting into the connectors on the outside of the generator. When this happens the generator either starts on it's own or won't start at all. So if the switch doesn't resolve your issue, check for a multi wire plug running along the exterior of the generator box, pull it apart, make sure it's clean and reconnect. If you have some dialectric grease, (nonconductive grease available at auto parts stores) you can grease the connection to make it more waterproof before connecting it back together.
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor