Temperature Control Knob
WARNING: This page is about a different car, the 1994 Plymouth Colt, 1994 Mitsubishi Mirage, 1994 Eagle Summit, and 1994 Dodge Colt. However, it is still accessible from the selected car via links, so may be relevant.
When temperature control knob is rotated toward cool air position, upper side of heater core is blocked by blend-air door. As a result, all air from blower motor by-passes heater core and flows into passenger compartment as cool air.
When temperature control knob is rotated toward warm air position, blend-air door will block cool air path. Cool air from blower motor now passes through heater core for maximum heating.
With temperature knob in middle position, blend-air will split air stream into 2 branches, one passing through heater core and on by-passing heater core. Various combinations of warm and cool air are available to meet various temperature requirements.