Cold Air Purge

The humid air which collects around the heater core inside the air distribution module could cause windshield togging during a start in cool weather with a still warm engine. A purge routine is programmed into the H-A/C control to prevent this. With coolant temperature at least 16°C (60°F) and with the blower motor and the air distribution in the AUTO mode, the air valves move to guide the airflow away from the windshield. During the first five seconds, while the air valves are moving into position, the blower motor does not run. Then, during the next 30 seconds a low blower motor speed purges the moist air from the system. After that the system goes to the normal operating mode.