Pinpoint Test I: Incorrect/Erratic Direction Of Airflow from Outlets - EATC
Climate Control System
Pinpoint Tests
Pinpoint Test I: Incorrect/Erratic Direction of Airflow from Outlets - EATC
Normal Operation
Under normal operation, the HVAC module is provided vacuum from the engine. When a mode is selected, vacuum is applied to the desired vacuum control motor that is connected to the mode door you want to control.
This pinpoint test is intended to diagnose the following:
- HVAC module
- Heater control valve
- Vacuum control motor
- Stuck or bound linkage or door
- Leaking or plugged vacuum hose
PINPOINT TEST I: INCORRECT/ERRATIC DIRECTION OF AIRFLOW FROM OUTLETS - EATC
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I1 CHECK THE AIRFLOW IN EACH SETTING
- Ignition ON.
- With the engine running, check the airflow in each manual override setting on the HVAC module during engine idle and under acceleration.
- Is the airflow correct in each manual override setting?
Yes
The system is operating normally.
No
If the airflow is from the defrost outlet only in all settings, GO to I2.
If the airflow is incorrect in one setting only, NOTE the non-functional setting. GO to I10.
If the airflow is incorrect in MAX only, GO to I14.
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I2 CHECK FOR VACUUM AT THE CHECK VALVE
- Disconnect the vacuum check valve vacuum source line and connect the vacuum pump.
- Is manifold vacuum present at the check valve vacuum source line?
Yes
GO to I3.
No
REPAIR or INSTALL a new check valve vacuum source line. TEST the system for normal operation.
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I3 CHECK THE VACUUM CHECK VALVE FOR BLOCKAGE
- Reconnect the vacuum source line to the vacuum check valve.
- Disconnect the vacuum reservoir line and the HVAC module vacuum line from the vacuum check valve and plug one port.
- Check for manifold vacuum at the open port on the vacuum check valve.
- Is manifold vacuum present at the open port on the vacuum check valve?
Yes
GO to I4.
No
INSTALL a new vacuum check valve. TEST the system for normal operation.
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I4 CHECK THE VACUUM CHECK VALVE
- Ignition OFF.
- Disconnect: A/C Vacuum Check Valve.
- Connect the vacuum pump to the vacuum check valve and attempt to pull a vacuum.
- Can a vacuum be pulled on the vacuum check valve?
Yes
GO to I5.
No
INSTALL a new vacuum check valve. TEST the system for normal operation.
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I5 CHECK THE VACUUM RESERVOIR LINE FOR BLOCKAGE
- Disconnect the vacuum reservoir line at the vacuum reservoir.
- Connect the vacuum pump to the vacuum reservoir line at the vacuum check valve connection and attempt to pull a vacuum.
- Can a vacuum be pulled on the vacuum reservoir line?
Yes
REPAIR or INSTALL a new vacuum reservoir line. TEST the system for normal operation.
No
GO to I6.
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I6 CHECK THE VACUUM RESERVOIR LINE FOR LEAKS
- Plug the vacuum reservoir line at the vacuum reservoir connection.
- Leak test the vacuum reservoir line using the vacuum pump.
- Does the vacuum reservoir line leak?
Yes
REPAIR or INSTALL a new vacuum reservoir line. TEST the system for normal operation.
No
GO to I7.
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I7 CHECK THE VACUUM RESERVOIR FOR A LEAK
- Connect the vacuum pump reservoir line to the vacuum reservoir.
- With the vacuum pump connected to the vacuum reservoir line, leak test the vacuum reservoir.
- Does the vacuum reservoir leak?
Yes
INSTALL a new vacuum reservoir. TEST the system for normal operation.
No
GO to I8.
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I8 CHECK THE HVAC MODULE VACUUM SOURCE LINE FOR BLOCKAGE
- Disconnect: HVAC Module Vacuum Connector.
- Connect the vacuum pump to the HVAC module vacuum source line and attempt to pull a vacuum.
- Can a vacuum be pulled on the HVAC module vacuum source line?
Yes
REPAIR or INSTALL a new HVAC module vacuum source line. TEST the system for normal operation.
No
GO to I9.
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I9 CHECK THE HVAC MODULE VACUUM SOURCE LINE FOR LEAKS
- Plug the HVAC module vacuum source line at the vacuum check valve connection.
- Leak test the HVAC module vacuum source line using the vacuum pump.
- Does the HVAC module vacuum source line leak?
Yes
REPAIR or INSTALL a new HVAC module vacuum source line. TEST the system for normal operation.
No
INSTALL a new HVAC module. TEST the system for normal operation.
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I10 CHECK THE VACUUM CONTROL MOTOR LINE FOR BLOCKAGE
- Ignition OFF.
- Disconnect: HVAC Module Vacuum Connector.
- Disconnect the vacuum line from the appropriate vacuum control motor noted in Step I1.
- Connect the vacuum pump to the appropriate vacuum control motor line noted in Step I1, and attempt to pull a vacuum.
- Can a vacuum be pulled on the vacuum control motor line?
Yes
REPAIR or INSTALL a new vacuum harness. TEST the system for normal operation.
No
GO to I11.
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I11 CHECK THE VACUUM CONTROL MOTOR LINE FOR LEAKS
- Plug the vacuum control motor line at the vacuum control motor connection.
- Leak test the vacuum control motor line using the vacuum pump.
- Does the vacuum control motor line leak?
Yes
REPAIR or INSTALL a new vacuum harness. TEST the system for normal operation.
No
GO to I12.
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I12 CHECK THE VACUUM CONTROL MOTOR FOR LEAKS AND CORRECT OPERATION
- Connect the vacuum pump to the appropriate vacuum control motor and pull a vacuum.
- Does the vacuum control motor operate and hold vacuum?
Yes
GO to I13.
No
INSTALL a new vacuum control motor. TEST the system for normal operation.
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I13 CHECK THE MODE DOOR LINKAGE AND MOVEMENT
- Inspect the mode door linkage and verify correct movement of the mode door.
- Is the mode door or mode door linkage broken, binding or otherwise obstructed?
Yes
REPAIR the mode door or mode door linkage as necessary. TEST the system for normal operation.
No
INSTALL a new HVAC module. TEST the system for normal operation.
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I14 CHECK THE AIR INLET DOOR VACUUM CONTROL MOTOR LINE FOR BLOCKAGE
- Ignition OFF.
- Disconnect the air inlet door vacuum control motor vacuum connector.
- Disconnect the HVAC module vacuum connector and attempt to pull a vacuum on the RECIRC vacuum control motor line using the vacuum pump.
- Can a vacuum be pulled on the air inlet door vacuum control motor line?
Yes
REPAIR or INSTALL a new plenum vacuum harness. TEST the system for normal operation.
No
GO to I15.
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I15 CHECK THE AIR INLET DOOR VACUUM CONTROL MOTOR LINE FOR LEAKS.
- Plug the air inlet door vacuum control motor line at the RECIRC vacuum control motor connection.
- Leak test the air inlet door vacuum control motor line using the vacuum pump.
- Does the air inlet door vacuum control motor line leak?
Yes
REPAIR or INSTALL a new vacuum harness. TEST the system for normal operation.
No
GO to I16.
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I16 CHECK THE AIR INLET DOOR VACUUM CONTROL MOTOR FOR LEAKS AND CORRECT OPERATION
- Connect the vacuum pump to the air inlet door vacuum control motor and pull a vacuum.
- Does the air inlet door vacuum control motor operate and hold a vacuum?
Yes
GO to I17.
No
INSTALL a new air inlet door vacuum control motor. TEST the system for normal operation.
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I17 INSPECT THE AIR INLET DOOR LINKAGE AND MOVEMENT
- Inspect the air inlet door linkage and verify correct movement of the door.
- Is the air inlet door or air inlet door linkage broken, binding or otherwise obstructed?
Yes
REPAIR the air inlet door or air inlet door linkage as needed. TEST the system for correct operation.
No
INSTALL a new HVAC module. TEST the system for normal operation.
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