Re: Living in Maine in a Winnebago
By far the most common cause of the symptom that you have is the device called a "sail switch" in all RV furnaces has failed to close. If it does not close the propane valve will never open and there will be no heat. There are several common reasons for the sail switch not closing. It is there to insure that the furnace has ample air movement for safe operation before the propane is allowed to turn on and the flame to ignite.
One of the most common causes is voltage that is too low to turn the blower fast enough. The furnace runs on 12V-DC power and if that voltage drops below 11V it will not be reliable and it will never light if below 10.5V. Another common cause of this problem is that many insects like to build their nests in the furnace of an RV in the summer when it is not in use. Wasps, spiders and other things frequently use the flue as a home and when you turn on the furnace there is too little air flow to close that safety switch. There are also several other possible causes of this symptom.
Since it is now Oct. 12, I hope that you have gotten it to work, but most likely you will need to remove the furnace and clean it before things are going to work reliably. A great deal also depends upon what brand furnace you have. If it is an Atwood, most things can be cleaned from outside of the RV, but if it is from Suburban then it will probably have to be removed from the RV to do this job.