Operation CHARM: Car repair manuals for everyone.

Heater Mode

The sunload sensor assembly houses both the driver and passenger side sensors. The sunload sensor assembly 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 sunload sensor over the driver and passenger solar sensor signal circuit. A variable photo-diode resistor inside the sensor varies the voltage. That varied voltage provides a separate driver and passenger signal to the software inside the HVAC control module. The sensor also provides an average reading on the ambient light sensor signal circuit to the HVAC control module for the twilight sentinel feature. Remaining voltage from the sunload sensor assembly is sent back to the HVAC control module ground through the low reference circuit.