B0408

CIRCUIT DESCRIPTION
The HVAC control module commands the left air temperature actuator movement with one of three voltage signals applied to the left air temperature door control circuit. A low voltage of 0 volts moves the left air temperature door toward full hot. A voltage of 2.5 volts stops the actuator. A high voltage of 5 volts moves the left air temperature door toward full cold. The HVAC control module determines the current position HVAC the actuator by monitoring the feedback voltage of the left air temperature door position signal circuit. The feedback potentiometer position is a function of the actuator position. A high voltage indicates a full cold left air temperature door position. A low voltage indicates a full hot left air temperature door position. The HVAC control module controls the left air temperature door position in order to maintain the selected air temperature.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is turned ON.
^ Ignition voltage is between 9 - 16 volts.

CONDITIONS FOR SETTING THE DTC
^ Left air temperature position signal is less than 5 counts.
^ Left air temperature position signal is greater than 194 counts.
^ The left air temperature actuator actual total travel range max-min is less than or greater than the range limits.

ACTION TAKEN WHEN THE DTC SETS
^ The HVAC control module will continue to make use of whatever left air temperature actuator travel range is still available.
^ The DTC is stored in DTC information.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the HVAC control module no longer detects a failure.
^ The history DTC will clear after 50 fault free ignition cycles.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
^ A damaged or broken left air temperature actuator or mode door can cause this DTC to set.
^ If condition not present refer to Testing for Intermittent and Poor Connections in Diagnostic Aids.

TEST

Steps 1-5:

Steps 6-15: