B0233 - HVAC Systems - Automatic

Schematic:

CIRCUIT DESCRIPTION
The air mix actuator is an electronic stepper motor without a feedback circuit. It responds to voltage inputs from the heater and A/C control with precalibrated non-adjustable position settings. The heater and A/C control adjusts the air mix door actuator position to maintain the air temperature 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 air mix actuator motor control circuit is shorted to ground or shorted to B+ for more than 2 seconds.

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

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 50 fault free ignition cycles
^ The DTC can be cleared with a scan tool.

TEST DESCRIPTION

Steps 1-9:

The numbers below refer to the step numbers on the diagnostic table.
2. The air mix actuator can be driven to one of two positions using the COLD and HOT 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.