With the temperature switches at the HVAC control, the wished air temperature flap position can be put in. The selected values are sent to the HVAC control module via LIN-Bus. The HVAC control module supplies a 12 V reference voltage to the stepper motors and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motors put the mixed air flaps into the calculated position, in order to reach the selected temperature.

Check the following mechanical fault sources:

Schematic Reference

LINK 49327

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic HVAC Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Measure actual inside air temperature using a thermometer. Compare this value to the scan tool Passenger Compartment Air Temperature parameter. The measured temperature should be within 5°C (9°F) difference of parameter value.

⇒	If not within the specified range, refer to DTC B0163, B0183, or B1405.

2. Measure actual temperature using a thermometer at each of the duct temperature sensors. Compare this value to the appropriate scan tool Duct Actual parameter. The measured temperature should be within 5°C (9°F) difference of appropriate Duct Actual parameter value.

⇒	If not within the specified range, refer to DTC B0173, B0178, B0509, B0514 or B3933.

3. Measure actual evaporator temperature using a thermometer. Compare this value to the scan tool A/C Evaporator Temperature Sensor parameter. The measured temperature should be within 5°C (9°F) difference of parameter value.

⇒	If not within the specified range, refer to DTC B0173, B0178, B0509, B0514 or B3933.

4. Ignition ON, observe the scan tool Sunload parameter parameter. The reading should be between 50-1 150 W/m² and change with sunlight intensity.

⇒	If not within the specified range or not change, refer to DTC B0163, B0183, or B1405.

5. Engine is running, activate and deactivate the A/C Switch. Verify the A/C compressor can be activated and deactivated.

⇒	If the A/C compressor cannot be activated or deactivated, refer to Air Conditioning Compressor Malfunction.

6. Verify the engine reaches its operating temperature.

1. Ignition ON, put the left temperature knob in all positions. Verify the scan tool parameter Left Temperature Knob Position parameter. The reading should be between -6 to +6 and change with the knob position. At the left end position the reading should be 18 and at the right end position -18.

⇒	If not the specified value, replace the A26 HVAC Control

2. Ignition ON, put the right temperature knob in all positions. Verify the scan tool parameter Right Temperature Knob Position parameter. The reading should be between -6 to +6 and change with the knob position. At the left end position the reading should be 18 and at the right end position -18.

⇒	If not the specified value, replace the A26 HVAC Control

3. Verify the M6L Air Temperature Actuator - Left can be put into all positions.

⇒

If the M6L Air Temperature Actuator - Left cannot be put into all positions, replace the M6L Air Temperature Actuator - Left and verify the M6L Air Temperature Actuator - Left can be put into all positions. If the M6L Air Temperature Actuator - Left cannot be put into all positions, replace the K33 HVAC Control Module.

4. If all circuits test normal, replace the M6R Air Temperature Actuator - Right and verify the M6R Air Temperature Actuator - Right can be put into all positions. If the M6R Air Temperature Actuator - Right cannot be put into all positions, replace the K33 HVAC Control Module.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.