Do you know if your motorhome has an Automatic Transfer Switch? This allows the generator to provide 110 power automatically without having to physically connect the shore power cord to the receptacle. With the generator on, do your 12 volt lights work? Also, if you are able to start your generator with the house batteries, then the disconnect switch is working, but maybe the indicator light is burned out. As for the slide out not working, that stumps me. On some motorhomes, you have to engage the parking brake when activating the slides, but I don't know if that might apply to your type motorhome.