Air Mix Valve Position

The proper air mix valve position is determined by the heater and A/C programmer. In order to provide the proper mix of warm and cool air, the heater and A/C programmer monitors the following variables:

- Set temperature.
- Coolant temperature.
- Ambient air temperature.
- Air delivery mode.
- Inside air temperature.
- Engine RPM.
- Low side temperature.
- Blower speed.
- Sun load sensor.
- Mix motor feedback.

Based upon these inputs, the heater and A/C programmer can position the air mix valve for the appropriate blend of air through the evaporator core and heater core depending upon the current program number.