HVAC System

CIRCUIT DESCRIPTION
The heater and A/C control monitors the right heater duct via a RH air duct temperature sensor. 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
RH air duct temperature sensor signal (circuit 924) circuit stays at or near 0 volts.

ACTION TAKEN WHEN THE DTC SETS
^ The heater and A/C control stores a DTC 14 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 1-12:

The numbers below refer to the step numbers on the diagnostic table.
2. Scan tool uses a default value, this will not give accurate reading of sensor value if open or short to ground.
8. Tests for the possibility of a short to voltage.