Temperature Control Knob

When the temperature control knob is rotated fully counterclockwise, toward cool air position, the upper side of heater core is blocked by the 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 fully clockwise, 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 door will split air stream into two branches, one passing through the heater core and one by-passing the heater core. Various combinations of warm and cool air are available to meet various temperature requirements.