Circuit Description

WARNING: This page is about a different car, the 2006 Buick LaCrosse and 2006 Buick Allure. However, it is still accessible from the selected car via links, so may be relevant.

Air temperature sensors allow the HVAC control module to monitor the discharge duct air, outside air and inside air temperatures. The HVAC control module provides ground to the air temperature sensor through the low reference circuit. The HVAC control module monitors the voltage drop across the air temperature sensor thermistor by supplying a 5 volt reference to the signal circuit of the air temperature sensor for automatic control calculations. When the air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module can read voltage values and count values where 1 volt is approximately equal to 51 counts.

Outside Air Temperature Sensor refers to the ambient air temperature sensor.
Passenger Compartment Temperature Sensor refers to the inside air temperature sensor.
Output Air Temperature Sensor 1 refers to the upper left air temperature sensor.
Output Air Temperature Sensor 2 refers to the lower left air temperature sensor.
Output Air Temperature Sensor 3 refers to the upper right air temperature sensor.
Output Air Temperature Sensor 4 refers to the lower right air temperature sensor.