I own a Thor Citation 24ft. Sprinter diesel. Well, now I can't get the generator to crank over. Tried it from the inside switch and at the unit itself. Batteries are charged. Checked the breaker at the generator not tripped. All fuses and breakers are good in the panel. This is a propane run generator and just filled the tank. I'm new at this RV thing, so I'm learning as I go. Any thoughts?