So long as you don't have 'recirculate' selected, you have fresh air coming in! The fan speed will select how fast it comes in and the temperature control will determine whether it is heated or cooled, but it is fresh air from outside!
One of the most useful features on the newer climate control units is the 'A' - auto - mode, which will recirculate but switch to fresh air periodically to ensure the inside doesn't mist up. Thus its also the most economic way to use aircon.
just press the snowflake button and it will turn the compressor off...it will then stop chilling the air. if you turn the air con down to lo then it will just blow the air through with out chilling or heating it.