Circuit Description
WARNING: This page is about a different car, the 2003 Chevrolet Corvette. However, it is still accessible from the selected car via links, so may be relevant.
The HVAC control module monitors the ambient light on the inside of the vehicle via a light sensitive photodiode which is called a sunload sensor. The HVAC control module uses this information to compensate for the effect of the sun on the inside air temperature of the vehicle. When the sensor is in direct sunlight, the signal voltage is low. When the sensor is shaded, the signal voltage is high. The HVAC control module requests A/C compressor clutch engagement and controls the air temperature actuator door positions in order to maintain the selected air temperature.