motor home problem

I have a 1993 Rockwood motor home that has been parked in my shed for three years and nothing works like it used to. The alternator doesn't work, the two air conditioners don't work, the generator won't crank,the cummins diesel engine will crank and pump up the air. Where do I start? Roy

Alternator- sounds like you have electrical gremlins, probably the deadly combination of mice and corrosion, Alternators need to be excited by the battery to work. Have you changed the battery? With a known good battery check for voltage at the alternator and work your way between the battery and alternator checking each connection and repairing all damage you find. Still no joy, do the standard alternator check might even get the local auto parts to check it for you if you can bring it in. AC units check for voltage at each unit once you get power to then if they don't work take them to a company that services them. They might not work because of stuck or corroded relays/contacts or they may be low on refrigerant either way it's probably not a DIY fix. Generator tell us more- gas diesel or propane? Does it turn over and not start? Where does it get starting voltage, from the powertrain battery, coach battery or its own battery? If gas pull unit & empty fuel, clean fuel system (Tank to carb) replace fuel filter and plug, verify spark and it should run. Diesel- trouble shoot as any diesel- verify compression and fuel delivery. Propane verify fuel I would suspect a bad regulator or the device that heats the liquid propane to become becomes gas (if it has one) or your propane system may have a leak and ran out, or got mice & wasps messing with stuff. How are the stove, furnace, refrigerator and water heater?

Thanks for your help. I replaced the battery and the diesel engine cranks ok. The onan generator is propane and I turned the gas off several months ago, however the gen. won't crank so I haven't opened the valve. I have had mice and mud dobbers into everything. I will keep trying. Roy