Temperature Control Knob
WARNING: This page is about a different car, the 2001 Pontiac Bonneville and 2000 Pontiac Bonneville. However, it is still accessible from the selected car via links, so may be relevant.
The rotary temperature control knob is a potentiometer which sends voltage signal to temperature door actuator. Voltage signal varies according to temperature knob position. In full cold position, less than one volt is applied to temperature door actuator. In full hot position, battery voltage is applied to temperature door actuator.