GM Service Manual Online
For 1990-2009 cars only

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

Door Lock Window Switch Ignition

1

1

--

--

Window Control Module Ignition

1

1

--

--

Window Control Module Signal

1

1

1

--

Front Window Motor Control

1

1

1

--

Window Control Module Ground

--

1

1

--

1. Front Power Window Malfunction

Circuit/System Description

The power window system will operate any time the ignition is the ACC or RUN position. The power window system will also operate whenever the body control module (BCM) is in RAP mode. The door lock window switch contains individual window switches for each power window. Both windows are controlled up and down from the door lock window switch.

Each power window contains a reversible power window motor. The direction the window travels is dependent upon the polarity of the supply voltage. By reversing polarity of the supply voltage the window motor will move up or down. Each power window motor is internally circuit breaker protected.

Reference Information

Schematic Reference

Moveable Window Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Windows Description and Operation

Electrical Information Reference

    •  Circuit Testing
    •  Connector Repairs
    •  Testing for Intermittent Conditions and Poor Connections
    •  Wiring Repairs

Circuit/System Verification

  1. Ignition ON, command each window UP and DOWN using the appropriate window switch on the door lock window switch. Each window should perform the UP and DOWN functions from each switch.
  2. Command the express down function of the driver and passenger door windows by pressing the LF and RF window switches and releasing. The driver and passenger windows should perform the express down function.
  3. If the function does not perform as specified, replace the window control module.

Circuit/System Testing

  1. Ignition OFF, disconnect the X2 harness connector at the door lock window switch.
  2. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 1 and ground.
  3. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  4. Ignition OFF, connect the X2 harness connector at the door lock window switch and disconnect the harness connector at the window control module.
  5. Test for less than 1 ohm between the ground circuit terminal 5 and ground.
  6. If greater than the specified range, test the ground circuit for an open/high resistance.
  7. Ignition ON, verify that a test lamp illuminates between the ignition circuit terminal 8 and ground.
  8. If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
  9. Connect a test lamp between the appropriate signal circuit terminal listed below and ground:
  10. • Terminal 12
    • Terminal 9
  11. Command the power window DOWN by using the appropriate window switch on the door lock window switch. The test lamp should illuminate during the DOWN command.
  12. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the door lock window switch.
    If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the door lock window switch.
  13. Connect a test lamp between the appropriate signal circuit terminal listed below and ground:
  14. • Terminal 6
    • Terminal 3
  15. Command the power window UP by using the window switch on the door lock window switch. The test lamp should illuminate during the UP command.
  16. If the test lamp is always OFF, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the door lock window switch.
    If the test lamp is always ON, test the signal circuit for a short to voltage. If the circuit tests normal, test or replace the door lock window switch.
  17. Ignition OFF, connect the harness connector at the window control module and disconnect the harness connector at the appropriate window motor.
  18. Test for less than 5 ohms between the control circuit terminal A and ground.
  19. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the window control module.
  20. Test for less than 5 ohms between the control circuit terminal B and ground.
  21. If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the window control module.
  22. Ignition ON, connect a test lamp between the control circuit terminal A and control circuit terminal B.
  23. Command the power window UP and DOWN by using the window switch on the door lock window switch. The test lamp should illuminate during the UP and DOWN command.
  24. If the test lamp is always OFF during either for the commands, test either control circuit for a short to ground. If the circuits test normal, replace the window control module.
  25. If all circuits test normal, test or replace the front window motor.

Component Testing

Window Motor

    Important: When performing the following tests, make sure that the window motor is not all ready in the position the test is attempting to produce.

  1. Ignition OFF, disconnect the harness connector at the appropriate window motor
  2. Install a 20A fused jumper wire between the control terminal A and 12V. Momentarily install a jumper wire between the control terminal B and ground. The window motor should perform the UP/DOWN function.
  3. If the function does not perform as specified, replace the window motor.
  4. Reverse the jumper wires, the window motor should perform the DOWN/UP function.
  5. If the function does not perform as specified, replace the window motor.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Power Mirror Switch Replacement
    •  Front Side Door Window Regulator Motor Replacement
    •  Front Door Module Replacement