Operation CHARM: Car repair manuals for everyone.

Cabin Temperature Sensor / Switch: Description and Operation

SUNLOAD SENSORS

The sunload sensors provides the HVAC control module software with the amount of sun light entering the driver and passenger side through the windshield. A 5-volt reference signal is sent from the HVAC control module to the left and right sunload sensor over the driver and passenger solar sensor signal circuits. A variable photo-diode resistor inside the sensor varies the voltage. That varied voltage provides a signal to the software inside the HVAC control module. Remaining voltage from the sunload sensors are sent back to the HVAC control module ground through the low reference circuit.