2008 Chevrolet Tahoe Owner's Manual - Page 205

Sensors The interior temperature sensors located in the headliner above the driver side seat and if equipped, in the headliner above the second row seats measure the temperature of the air inside the vehicle. 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. 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. 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. 3-31