We have had a sharpe convection microwave in our stick house for many years. I have found that all the micro switches do not hold up to the current draw over time and fail now and then (especially if you use the covection part a lot). I'm not sure if the RV ones are any differenct. However, I have had ours apart several times and tracked down the culprit switch with an multimeter and replaced them. Back in business quite easily. If you are at all handy with a multimeter and reading the schematic inside the carver, it is worth a shot. Carefull, some switches are hooked up to the normally open blade, and others to the normally closed (labeled no and nc).
good luck,
jeff
Jeff
Retired AF, retired contractor, really retired!
2007 Winnebago Journey 34H 350hp Cat
2005 Jeep Grand Cherokee Toad with Air Force One