B0238

CIRCUIT DESCRIPTION
The mode actuator is an electronic stepper motor without a feedback circuit. It responds to voltage inputs from the HVAC control module with precalibrated, non-adjustable position settings. Zero volts drives the actuator in one direction while 12 volts drives it in the opposite. The HVAC control module adjusts the mode actuator position to direct airflow from the outlets selected by the vehicle occupants.

CONDITIONS FOR RUNNING THE DTC
^ The ignition is turned ON.
^ DTC B1327 must not be current.

CONDITIONS FOR SETTING THE DTC
The mode door control circuit is shorted to ground or shorted to battery voltage for more than 2 seconds.

ACTION TAKEN WHEN THE DTC SETS
Control of the mode door position will be disabled.

CONDITIONS FOR CLEARING THE DTC
^ The DTC will become history if the HVAC control module no longer detects a failure.
^ A history DTC clears after 50 fault-free ignition cycles
^ Use the scan tool in order to clear the DTCs.

TEST DESCRIPTION

Steps 1-9:

The numbers below refer to the step numbers on the diagnostic table.
2. The mode actuator can be driven to one of two positions using the Defrost and A/C command keys on the scan tool. The scan tool displays module output as a percentage of maximum control voltage. It does not indicate true actuator or door position.
3. This step verifies that the actuator is receiving the control voltage.