Mode Control Knob
WARNING: This page is about a different car, the 1999 Dodge Pickup, 1999 Dodge Durango, 1999 Dodge Dakota, and 1999 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
Mode rotary switch is used to change direction of air flow. There are 7 different modes of operation: recirculation, panel with A/C, floor/panel, panel without A/C (vent), floor, floor/defrost, and defrost.