Air Cond set to "auto" or "on"?

As stated earlier, the auto/on switch only controls the air fan, not the compressor. The compressor will cycle on the room temperature at the same rate in either switch position. I personally turn the fan to the on position when it gets extremely hot outside to help eliminate any hot spots inside my 32' trailer by causing constant air circulation. Otherwise, during regular outside temperatures, I leave it in auto mode. The only things that will cause freeze ups are a dirty sir filter (gets dirty faster with the constant fan operation) or trying to have the interior temperatures in the 60's or colder.