Temperature Control Lever
WARNING: This page is about a different car, the 1995 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
The temperature lever mechanically operates a cable to adjust the temperature blend door. Temperature blend door is in the plenum assembly. When temperature lever is in COOL position, temperature blend door stops airflow to heater core. When lever is in the WARM position, air is directed through the heater core. When lever is in intermediate positions, heated air is blended with cooler incoming air to achieve desired temperature.