B3531

CIRCUIT DESCRIPTION
The auxiliary mode actuator is an electronic device that incorporates a stepper motor and feedback potentiometer. The auxiliary HVAC control module control assemblies; control the auxiliary mode door position by sending a control signal to the actuator. The signal's value is dependent upon the desired mode selected by the vehicle occupants. As the actuator moves, the potentiometer produces the actual door position signal that is sent to the rear auxiliary HVAC control module. The rear auxiliary HVAC control module continues to command the actuator to move until the desired and actual values are equal. The door directs airflow through the outlets as selected by the vehicles occupants.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is ON.
^ Ignition voltage is between 9-16 volts.
^ An auxiliary mode actuator positional change is attempted.

CONDITIONS FOR SETTING THE DTC
The actual auxiliary mode door position differs from the commanded auxiliary mode door position by 4 counts or more.

ACTION TAKEN WHEN THE DTC SETS
The auxiliary mode actuator is considered stalled and the HVAC control module will command the auxiliary mode actuator to stop rotation (2.5 V).

CONDITIONS FOR CLEARING THE DTC
^ If the rear auxiliary HVAC control module no longer detects a failure, then the DTC will become history.
^ The history DTC will clear after 50 ignition cycles without a failure.
^ The DTC can be cleared with a scan tool.

DIAGNOSTIC AIDS
^ A dead zone exists in a range 10 counts above or below the auxiliary mode door max or auxiliary mode door mm positions. When the auxiliary mode door actual data parameter is within the dead zone, the DTC will not set. If the auxiliary mode door commanded data parameter differs from the auxiliary mode door actual data parameter by 4 counts or more outside the dead zone, the DTC will set.
^ A damaged or broken auxiliary mode door and or actuator can cause this DTC to set.

TEST

Steps 1-7:

Steps 8-14: