Originally Posted by tanyajayne
The fan does not fun, it does nothing at all.
If it does nothing at all - not even the fan runs - you probably don't have power going to the furnace. Could be the thermostat. The thermostat in our old popup was rather flimsy to be nice about it. Once you get the camper out again, the first step would be to "follow the power" by seeing if you have 12V at the thermostat, then with the thermostat set high enough to call for heat see if you have power at the furnace.
A multi-meter is a very useful tool for any rv owner to keep around for troubleshooting problems like this one and checking batteries. If you haven't used one before, they aren't difficult and the instruction manual will help you out. Since many of these problems tend to happen when you are out the woods someplace far from home, it is good to be able to have some basic tools so you can deal with the gremlins that occasionally pop up.