Service Information

Orlando

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	Short to Ground	Open/High Resistance	Short to Voltage	Signal Performance
Stepper Motors 12V Reference	B023A 02, B0223 06, B0233 06, B0408 06	B0223 06, B0233 06, B0408 06	--	--
Air Temperature Actuator - Left Control 1	B0408 06	B0408 06	B0408 01	1
Air Temperature Actuator - Left Control 2	B0408 06	B0408 06	B0408 01	1
Air Temperature Actuator - Left Control 3	B0408 06	B0408 06	B0408 01	1
Air Temperature Actuator - Left Control 4	B0408 06	B0408 06	B0408 01	1
1. Air Temperature Malfunction

With the temperature switch at the HVAC controls, the desired air temperature flap position can be put in. The selected value is passed to the HVAC control module via the LIN-Bus. The HVAC control module supplies a 12 V reference voltage to the stepper motor and energizes the 4 stepper motor coils with a pulsed ground signal. The stepper motor puts the mixed air flap into the calculated position, in order to reach the selected temperature.

Diagnostic Aids

Check the following mechanical fault sources:

•	Air distribution box

•	Air distribution hoses/air distribution ducts

Reference Information

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

Ignition ON, 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 B3933
If within the specified range
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
If the A/C compressor can be activated and deactivated
Verify the engine reaches its operating temperature.

Circuit/System Testing

Ignition ON, turn the temperature knob in all positions. Verify the scan tool Left Temperature Knob Position parameter. The reading should be between -7 to +7 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 Controls.
If the specified value
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.
If the M6L Air Temperature Door Actuator - Left can be put into all positions
All OK.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

•	Heater and Air Conditioning Control Replacement

•	Temperature Valve Actuator Replacement : Right Hand Drive → Left Hand Drive

•	Control Module References for HVAC control module replacement, setup, and programming