Cynthia: Sorry about your problems, but I would suggest you read the link in Post #5 above. Then I think you can strike your furnace/AC as a problem. The AC fan is SUPPOSED to run with the furnace. Think of it as a ceiling fan. It takes the hot air that rises to the ceiling and redistributes it so you don't have a great a temperature gradient from the floor to the ceiling. I'm guessing your AC vents are out near the ends of the camper while the furnace cold air return is probably in the middle of the camper.
1988 Coleman Sequoia - popup (1987-2009) - outlasted 3 Dodge Grand Caravans!
2012 Roo19 - hybrid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado 1500 Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10