My front Coleman did the same thing. If yours is a Coleman then the first thing to do, and the cheapest, is remove the filter and reach up in there and reseat the connectors on the circuit board that is visible. Disconnect the coach power first. That fixed my problem. If that doesn't fix yours then you can start looking for more expensive solutions.
2004 Hurricane 32R (F53)
2010 Ford Ranger 4X4
2009 Kymco Xciting 500Ri
1 wife and 7 cats
My problem was the high speed fan would work intermittently or not at all. I think the problem is the same though.
The controller has 3 little relays mounted on a PCB board. One is for the high speed setting and one is for low speed. They really aren't substantial enough to handle the load of the fan. The points burn up. I could not find replacement parts locally and ended up swapping the relays around. This lasted for 2 yrs and now I'm running to issues again.
Coleman's fix is to replace the PCB board. I did find the relays (JZ-1aF-12) were suppose to be available @ www.onlinecomponents.com. if you're good with a soldering iron.