Circuit Description

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Air temperature sensors allow the HVAC control module to monitor the temperature of the discharge air in the HVAC ducts. The module applies 5 volts to internal input resistors that are connected to the signal circuits of the air temperature sensors. The module provides ground to the air temperature sensors through the low reference circuit. The HVAC control module monitors the voltage drops across the air temperature sensors and uses the inputs for automatic control calculations. When the duct air temperatures are cold, the resistances of the sensors are high and the voltage signals are high. When the duct air temperatures are hot, the resistances of the sensors are low and the voltage signals are low. The HVAC control module converts the voltage values to count values where 1 volt is approximately equal to 51 counts.

DTC B0158 is for the Outside Air Temperature Sensor
DTC B0163 is for the Passenger Compartment Air Temperature Sensor
DTC B0168 is for the Passenger Compartment Air Temperature Sensor Auxiliary
DTC B0173 is for the Left Upper Air Temperature Sensor
DTC B0178 is for the Left Lower Air Temperature Sensor
DTC B0509 is for the Right Upper Air Temperature Sensor
DTC B0514 is for the Right Lower Air Temperature Sensor
DTC B3578 is for the Auxiliary Upper Air Temperature Sensor
DTC B3583 is for the Auxiliary Lower Air Temperature Sensor