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Air Temperature Malfunction



Air Temperature Malfunction

Diagnostic Instructions
- Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
- Review Strategy Based Diagnosis for an overview of the diagnostic approach.
- Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information







Circuit/System Description
With the temperature switches at the Radio/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 put in temperature.

Diagnostic Aids
Check the following mechanical fault sources:
- Air distribution box
- Air distribution hoses/air distribution ducts

Reference Information

Schematic Reference
HVAC Schematics

Connector End View Reference
Component Connector End Views

Description and Operation
Automatic HVAC Description and Operation

Electrical Information Reference
- Circuit Testing
- Connector Repairs
- Testing for Intermittent Conditions and Poor Connections
- Wiring Repairs

Scan Tool Reference
Control Module References for scan tool information

Circuit/System Verification
1. Ignition ON, 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.
2. If not within the specified range, refer to DTC B0163, B0183, or B1405.
3. 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.
4. If not within the specified range, refer to DTC B0173, B0178, B0509, B0514, B0519, B3583, or B3933.
5. 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.
6. If not within the specified range, refer to DTC B0173, B0178, B0509, B0514, B0519, B3583, or B3933.
7. Observe the scan tool Sunload parameter. The reading should be between 50-1 150 W/m2 and change with sunlight intensity.
8. If not within the specified range or not change, refer to DTC B0163, B0183, or B1405.
9. Engine is running, activate and deactivate the A/C switch. Verify the A/C compressor can be activated and deactivated.
10. If the A/C compressor cannot be activated or deactivated, refer to Air Conditioning Compressor Malfunction (LAU, LBR, LBS, LDK, or LHU) or Air Conditioning Compressor Malfunction (LLU).
11. Verify the engine reaches its operating temperature.

Circuit/System Testing
1. Ignition ON, turn the left temperature knob in all positions. Verify the scan tool Left Temperature Knob Position parameter. The reading should correspond to the selected temperature.
2. If not the specified value, replace the A20 Radio/HVAC Controls.
3. Ignition ON, turn the right temperature knob in all positions. Verify the scan tool Right Temperature Knob Position parameter. The reading should correspond to the selected temperature.
4. If not the specified value, replace the A20 Radio/HVAC Controls.
5. Press and release the AUTO Switch. Verify the scan tool Auto HVAC Button parameter changes between Active and Inactive.
6. If not the specified value, replace the A20 Radio/HVAC Controls.
7. Press and release the ZONE Switch. Verify the scan tool MULTI-ZONE Switch parameter changes between Active and Inactive.
8. If not the specified value, replace the A20 Radio/HVAC Controls.
9. Verify the M6L Air Temperature Door Actuator - Left can be put into all positions.
10. If the M6L Air Temperature Door Actuator - Left cannot be put into all positions, replace the M6L Air Temperature Door Actuator - Left and verify the M6L Air Temperature Door Actuator - Left can be put into all positions. If the M6L Air Temperature Door Actuator - Left cannot be put into all positions, replace the K33 HVAC Control Module.
11. If all circuits test normal, replace the M6R Air Temperature Door Actuator - Right and verify the M6R Air Temperature Door Actuator - Right can be put into all positions. If the M6R Air Temperature Door Actuator - Right cannot be put into all positions, replace the K33 HVAC Control Module.

Repair Instructions
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
- Temperature Valve Actuator Replacement - Left Side (Right Hand Drive) Temperature Valve Actuator Replacement - Left Side (Left Hand Drive)
- Temperature Valve Actuator Replacement - Right Side (Left Hand Drive)
- Instrument Panel Lower Center Trim Panel Replacement
- Control Module References for HVAC control module replacement, setup, and programming
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