Hey all, I'm a new popup owner, have been camping a few times, and last time I was working/cleaning in the camper I noticed that my furnace (and fridge...thats another thread) wasn't firing, even though the fan was running. After some extensive research, mostly on here, and a bit on some recommended links (bryantrv) I learned how these furnaces worked, found my culprit to be the sail switch, and learned how to pull the furnace so I could correct the problem, which appeared to be the sail switch rubbing on the bottom of the furnace housing. While I had it apart, I also found a MASSIVE mud-dobber nest inside just above the fan wheel, which probably wasn't helping anything. Now it fires up on the first try. My other problem is the on/off switch on the thermostat...its kinda bent, and won't make good contact, so I'm going to bypass it and install a rocker switch in the same housing. Cheaper than a new thermostat. Thanks so much to this forum...ya'll are great!