2008 Chevrolet Silverado 1500 Pickup Owner's Manual - Page 212

Sensors The solar sensor, located in the defrost grille, in the middle of the instrument panel, monitors the solar radiation. Do not cover the solar sensor or the system will not work properly. The climate control system uses the information from these sensors to maintain your comfort setting by adjusting the outlet temperature, fan speed, and the air delivery mode. The system may also supply cooler air to the side of the vehicle facing the sun. The recirculation mode will also be used as needed to maintain cool outlet temperatures. Defogging and Defrosting Fog on the inside of the windows is a result of high humidity (moisture) condensing on the cool window glass. This can be minimized if the climate control system is used properly. There are two modes to clear fog or frost from the windshield. Use The interior temperature sensor, located in the headliner, measures the temperature of the air inside the vehicle. H and G to select the defog or defrost modes. -(Defog): There is also an exterior temperature sensor located behind the front grille. This sensor reads the outside air temperature and helps maintain the temperature inside the vehicle. Any cover on the front of the vehicle could cause a false reading in the displayed temperature on the rearview mirror. Press this button to clear the windows of fog or moisture and warm the passengers. This mode directs air to the windshield, floor outlets, and side window vents. When this mode is selected, the system turns off recirculation and runs the air conditioning compressor unless the outside temperature is close to freezing. The recirculation mode cannot be selected while in the defog mode. Do not drive the vehicle until all the windows are clear. 3-34