Circuit Description
WARNING: This page does not describe the selected car, but rather 7 other vehicles, including the 2002 GMC Yukon XL, 2002 GMC Yukon, 2002 Chevrolet Tahoe, 2002 Chevrolet Suburban, and 2002 Chevrolet Avalanche. However, it is still accessible from the selected car via links, so may be relevant.
The HVAC control module monitors the outside ambient air temperature via an ambient air temperature sensor. When the air is cold, the sensor resistance voltage and the signal voltage are high. When the air is warm, the sensor resistance voltage and the signal voltage are low.