From a previous post of mine:
After setting fan to Au, use on-off switch to move to heat (or cool as the case may be) and select temp using + - keys. When heat is called for, furnace blower will start and AC will not.
When in cool mode, Au will cause fan to turn on and off with need for cooling. Other modes of fan (hi or lo) will cause fan to run constantly when cool mode is selected and only AC compressor will cycle on and off as needed. If the neighbors are making too much noise at night, set fan to lo and thermostat to cool. Instant "white noise" generator to mask the sounds outside.
2012 Forest River Sunseeker 2300 Chevy