Air Distribution Control

Air distribution control is based on signals from ECC control module, which controls the ventilation and floor/defroster damper motor. When set to AUT (automatic) mode, the air distribution control circuit computes air distribution based on outside (ambient) temperature, the position of driver's side temperature control dial, and engine coolant temperature.

At low outside temperatures, the ECC control module selects floor/defrost setting, with a slight amount of bi-level air if sunshine is present. If outside temperature is between 50-66°F (10-19°C), a varying degree of bi-level air is selected. At temperatures greater than 68°F (20°C), all air is directed to instrument panel vents.

The ventilation air distribution setting is selected if driver's side control panel is set for maximum cooling. The floor/defrost setting is selected if maximum heating is selected. The defrost air distribution setting is selected if engine is cold and outside and interior temperatures are also low. This changes to varying degrees of floor/defrost air distribution as engine coolant temperature increases. The transition from defroster to floor/defroster setting takes place more quickly in sunshine.