Diagnostic Routine Q
Diagnostic Routine Q
Diagnostic Overview
The Temperature Control Is Inoperative or Does Not Operate Correctly - RH
Refer to Wiring Diagram Set 55 for schematic and connector information Electrical Diagrams.
Normal Operation and Fault Conditions
To rotate the temperature blend door actuator, the HVAC (Heating, Ventilation, and Air Conditioning) module supplies voltage and ground to the temperature blend door actuator through the door actuator motor circuits. To reverse the temperature blend door actuator rotation, the HVAC (Heating, Ventilation, and Air Conditioning) module reverses the voltage and ground circuits.
The temperature blend door actuator feedback resistors are supplied a ground from the HVAC (Heating, Ventilation, and Air Conditioning) module by the temperature blend door actuator return circuits and a 5-volt reference voltage on the temperature blend door actuator reference circuits. The HVAC (Heating, Ventilation, and Air Conditioning) module reads the voltage on the temperature blend door actuator feedback circuits to determine the temperature blend door actuator position by the position of the actuator feedback resistor wiper arm.
During an actuator calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module drives the temperature blend door until the door reaches both internal stops in the HVAC (Heating, Ventilation, and Air Conditioning) case. If the temperature blend door is temporarily obstructed or binding during a calibration cycle, the HVAC (Heating, Ventilation, and Air Conditioning) module may interpret this as the actual end of travel for the door. When this condition occurs and the HVAC (Heating, Ventilation, and Air Conditioning) module commands the actuator to its end of travel, the airflow may not be the expected temperature.
DTC Fault Trigger Conditions
Pinpoint Test
NOTE: The RH (Right Hand) temperature blend door actuator connector in the pinpoint test is difficult to access. Before disconnecting the RH (Right Hand) temperature blend door actuator, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
1. CHECK THE HVAC (Heating, Ventilation, and Air Conditioning) MODULE FOR DTCs (Diagnostic Trouble Codes)
1. Ignition ON.
2. Using a scan tool, perform a HVAC (Heating, Ventilation, and Air Conditioning) module self-test.
Are any DTCs (Diagnostic Trouble Codes) present?
2. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR OPERATION USING ACTIVE COMMANDS
1. Start the engine.
2. Run the engine until it reaches normal operating temperature.
3. Using a scan tool, view HVAC (Heating, Ventilation, and Air Conditioning) module PIDs (Parameter Identifications).
4. Select PANEL mode on the HVAC (Heating, Ventilation, and Air Conditioning) controls.
5. Select the highest blower motor setting.
6. Monitor airflow while using the scan tool to operate the HVAC (Heating, Ventilation, and Air Conditioning) module active command RIGHT_BLEND, increasing and decreasing the percentage value.
Does the airflow temperature change between warm and cold when the active command is changed?
3. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
3. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
4. Measure:
Are the resistances greater than 10,000 ohms?
4. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
4. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
5. Ignition ON.
6. Measure:
Is any voltage present?
5. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR MOTOR CIRCUITS FOR AN OPEN
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
3. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
4. Measure:
Are the resistances less than 3 ohms?
6. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR MOTOR CIRCUITS FOR A SHORT TOGETHER
NOTE: Access to the connector in the following step is difficult. Before carrying out this step, visually inspect the actuator and its harness for obvious damage. If no damage is evident, proceed with the test.
1. Ignition OFF.
2. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
3. Measure:
Is the resistance greater than 10,000 ohms?
7. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO GROUND
1. Ignition OFF.
2. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
4. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
5. Measure:
Is the resistance greater than 10,000 ohms?
8. CHECK THE SIGNAL RETURN CIRCUIT FOR A SHORT TO THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR FEEDBACK CIRCUIT
1. Measure:
Is the resistance greater than 10,000 ohms?
9. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR FEEDBACK CIRCUIT FOR A SHORT TO VOLTAGE
1. Ignition OFF.
2. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228A.
3. Disconnect: HVAC (Heating, Ventilation, and Air Conditioning) Module C228B.
4. Disconnect: RH (Right Hand) Temperature Blend Door Actuator.
5. Ignition ON.
6. Measure:
Is any voltage present?
10. CHECK THE REFERENCE VOLTAGE CIRCUIT FOR AN OPEN
1. Ignition OFF.
2. Measure:
Is the resistance less than 3 ohms?
11. CHECK THE REFERENCE VOLTAGE CIRCUIT FOR A SHORT TO THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR FEEDBACK CIRCUIT
1. Ignition OFF.
2. Measure:
Is the resistance greater than 10,000 ohms?
12. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR FEEDBACK CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
13. CHECK THE RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR RETURN SIGNAL RETURN CIRCUIT FOR AN OPEN
1. Measure:
Is the resistance less than 3 ohms?
14. CHECK FOR CORRECT RH (Right Hand) TEMPERATURE BLEND DOOR ACTUATOR OPERATION
1. Disconnect and inspect the RH (Right Hand) temperature blend door actuator connector.
2. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
3. Reconnect the RH (Right Hand) temperature blend door actuator connector. Make sure it seats and latches correctly.
4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
5. Operate the system and determine if the concern is still present.
Is the concern still present?
15. MODULE ACTUATOR POSITION CALIBRATION
NOTE: The purpose of the module actuator position calibration is to allow the HVAC (Heating, Ventilation, and Air Conditioning) module to reinitialize and calibrate the actuator stop points.
1. Ignition OFF.
2. Disconnect and inspect all HVAC (Heating, Ventilation, and Air Conditioning) module connectors.
3. Repair:
- corrosion (install new connector or terminals- clean module pins)
- damaged or bent pins- install new terminals/pins
- pushed-out pins- install new pins as necessary
4. Reconnect the HVAC (Heating, Ventilation, and Air Conditioning) module connectors. Make sure they seat and latch correctly.
5. Clear the DTCs (Diagnostic Trouble Codes).
6. Using a scan tool, perform HVAC (Heating, Ventilation, and Air Conditioning) Module self-test.
7. Select any position except OFF
8. NOTE: The HVAC (Heating, Ventilation, and Air Conditioning) module initializes and calibrates the actuators. Calibration of the actuators will take approximately 30 seconds.
Operate the system and verify the concern is still present.
Is the concern still present?
