HVAC System

CIRCUIT DESCRIPTION
The heater and A/C control monitors the inside air temperature via an inside air temperature sensor which is internal to the heater and A/C control. When the air is cold, the sensor resistance and signal voltage are high. When the air is warm, the sensor resistance and signal voltage are low. The heater and A/C control requests A/C compressor clutch engagement and controls the air temperature actuator door positions in order to maintain the selected air temperature on the heater and A/C control.

CONDITIONS FOR RUNNING THE DTC
The ignition is turned ON.

CONDITIONS FOR SETTING THE DTC
Inside air temperature sensor signal circuit stays at or near zero voltage.

ACTION TAKEN WHEN THE DTC SETS
^ The heater and A/C control stores a DTC 10 in memory.
^ The system will use a default value.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the heater and A/C control no longer detects a failure.
^ The history DTC will clear after 20 fault free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
If condition not present, refer to Testing for Intermittent and Poor Connections in Diagrams.

TEST DESCRIPTION

Steps 1-5:

The numbers below refer to the step numbers on the diagnostic table.
2. Determines if the malfunction is present.
3. The inside air temperature sensor is internal to the heater and A/C control. Replace the heater and A/C control to repair the malfunction.