Sunload Sensor

WARNING: This page is about a different car, the 2002 Buick LeSabre. 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 left and right sunload sensors. The 2 sensors are integrated into the sunload sensor assembly. Low reference and signal circuits enable the sensor to operate. As the light shining upon the sensor gets brighter, the sensor conductance increases. The sensor signal decreases as the conductance increases. The sensor operates within an intensity range between completely dark and bright. The sensor signal varies between zero-5 volts. The IPM converts the signal to a range between zero-255 counts.

The sunload sensor provides the IPM a measurement of the amount of light shining on the vehicle. 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.

If the IPM detects a malfunctioning sensor, then the IPM software will use a defaulted sunload value. The default action ensures that the HVAC system can adjust the inside air temperature near the desired temperature until the condition is fixed.