Ooops edited to add. I just realized that you stated that you had a non-ducted AC. The info below applies to my ducted AC. When I had a non-ducted I never did figure out how to turn the fan off.
Find and read the manual for your thermostat. My Dometic thermostat has Auto, Hi and Low settings. On Auto, the fan turns off when the AC turns off. It didn't really bother me that the fan ran all the time until I discovered that the furnace caused the AC fan to run all the time even though the furnace was in the floor and had its own blower. I was investigating replacing the thermostat when I stumbled upon the manual for mine and discovered it was a simple change at the thermostat.
