If no luck with info from above posts, can always call coleman. I forget where on the net I found it, but if you can find the number you can easily talk to their technicians on the phone (I got them on phone pretty easily when wanted to verify which size of unit was used on rig since dealer lied about other things on rig).
For simple test - set Fan Mode switch to ON, Thermostat (Heat/Off/Air) set to OFF, and then see if Hi/Low Fan Speed switch works.
edit - coleman phone numbers at:
http://rvcomfort.com/rvp/contact.php Seems like I called the main, corporate # and was then given option to talk with tech support, but can't remember for sure.