One common problem: The pilot light will not light or stay lit. Check to see whether the thermocouple is aligned correctly in the pilot flame. The flame should be mostly blue with a slight yellow tint to it.
Another problem is when you can't get the fan to run, but you have heat. First check the battery to see whether it has the proper charge. If that's not it, check the circuit breakers or fuses to make sure they are all working or not burned out. Finally, check the thermostat to see whether it is registering.
Sometimes in an RV furnace, the fan runs, but there is no heat coming out of it. If the fan starts, it means the thermostat is working. The lack of heat indicates an insufficient airflow, which could be caused by a bad regulator in the propane tank.
There are a few other things you should check if you have no heat but the fan is running. A lot of people forget to check whether the registers are open; or it could just be that some spiders have built a nest in your lines. In this case, simply clean out the lines. You can also check that your contacts for the electronic ignition are an eighth of an inch apart.
After cleaning, check fuses, lines, temperature and propane. If you are handy, check the furnace's motor. Ask the manufacturer of the furnace for specific instructions for your model. If all else fails, take your RV to your local dealer for repairs.
