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Home >> Chevrolet >> 2004 >> Impala SS >> Repair and Diagnosis >> External Pages >> Different car >> Section 458 (HVAC System - Automatic) >> Description and Operation >> Air Temperature Description and Operation >> HVAC Control Components >> HVAC Control Module >> Sunload Sensor
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Sunload Sensor

WARNING: This page is about a different car, the 2007 Chevrolet Malibu. However, it is still accessible from the selected car via links, so may be relevant.

The sunload sensor is a 2-wire photo diode. The vehicle uses a single sunload sensor. The sensor is integrated into the ambient light sensor assembly along with the ambient light sensor. Low reference and signal circuits enable the sensor to operate. As the sunload increases, the sensor signal decreases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between 0-5 volts. The sensor signal is read by the BCM, scaled appropriately and transmitted to the HVAC control module through the GM LAN Low Speed bus. Bright, or high intensity, light causes the vehicles inside temperature to increase. The HVAC system compensates for the increased temperature by diverting additional cool air into the vehicle.