Circuit Description
WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.
The HVAC control module monitors the ambient air temperature through an ambient air temperature sensor. The ambient air temperature sensor is a variable resistor. The HVAC control module supplies 5 volts to the ambient air temperature sensor signal circuit, and provides a low reference circuit. When the air is cold, the sensor resistance and signal voltage are high. When the air is warm, the sensor resistance and signal voltage are low. The HVAC control module displays the outside air temperature on the HVAC control module.