I would not suspect a sail switch in a three year old unit, although it is possible. If you have electricity available, having a 120 volt heater on hand can be useful if you run out of propane. Are you sure you have lots of propane. It will only run a handful of nights on full tanks. As stated, I would make sure you have a battery in the unit if you are using it. What if the power went off for a few hours. As stated your electric brakes require the battery for emergency stopping. My thermostat screwed up on my one mh, and would start the fan but not light the furnace. There again,not likely on such a new unit, but another possibility. Good luck. Let us know what you find.
