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

Relay Switch B+

1, 2

1, 2

--

--

Liftgate Release Switch Signal

1

1

1

--

Liftgate Release Relay Control

B3265 06

B3265 06

B3265 01

--

Liftgate Door Latch Control

2

2

2

--

Liftgate Release Switch Ground

--

1, 2

1, 2

--

Liftgate Door Latch Ground

--

2

2

--

1. Liftgate Release Switch Inoperative

2. Liftgate Release Inoperative

Circuit/System Description

The liftgate can be released by pressing the liftgate touchpad located in the handle above the license plate. All doors must be unlocked, the transaxle must be in park or a vehicle with a manual transaxle, the vehicle must be stationary for the liftgate to release.

Pressing the liftgate release switch closes a contact providing a ground for the liftgate release switch signal circuit. The body control module (BCM) will detect the voltage drop and command voltage to be supplied to the liftgate release relay control circuit thus energizing the L/GATE RELSE relay which provides voltage to the release actuator releasing the liftgate.

Reference Information

Schematic Reference

Release Systems Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Rear Hatch/Gate Description and Operation

Electrical Information Reference

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

Scan Tool Reference

Control Module References for scan tool information

Circuit/System Verification

  1. Ignition ON, observe the scan tool Liftgate Release Sw parameter while pressing and releasing the liftgate release switch. The parameter should change between Active and Inactive.
  2. If the parameter does not change, refer to Liftgate Release Switch Malfunction.
  3. Command the liftgate door latch to release by pressing the liftgate release switch. The liftgate door latch should release the liftgate.
  4. If the liftgate door latch does not release the liftgate, refer to Liftgate Release Malfunction.

Circuit/System Testing

Liftgate Release Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
  2. Test for less than 1 ohm between the ground circuit terminal D and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Liftgate Release Sw. parameter is Inactive.
  5. If not the specified value, test the signal circuit terminal B for a short to ground. If the circuit tests normal, replace the BCM.
  6. Install a 3A fused jumper wire between the signal circuit terminal B and ground. Verify the scan tool Liftgate Release Sw. parameter is Active.
  7. If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
  8. If all circuits test normal, test or replace the liftgate release switch.

Liftgate Release Malfunction

  1. Ignition OFF, disconnect the L/GATE RELSE relay.
  2. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.
  3. If the test lamp illuminates, test the control circuit for a short to voltage.
  4. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.
  5. If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.
  6. Ignition OFF, disconnect the harness connector at the liftgate door latch.
  7. Test for less than 1 ohm between the ground circuit terminal 3 and ground.
  8. If greater than the specified range, test the ground circuit for an open/high resistance.
  9. Connect the harness connector at the liftgate door latch.
  10. Ignition ON, connect a 20A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the liftgate door latch is activated.
  11. If the liftgate door latch does not activate, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, test or replace the liftgate door latch.
  12. Connect a test lamp between the control circuit terminal 86 and B+.
  13. Command the liftgate release ON and OFF by pressing and releasing the liftgate release switch. The test lamp should turn ON and OFF when changing between the commanded states.
  14. If the test lamp is always OFF, test the control circuit for an open/high resistance.
    If the test lamp is always ON, test the control circuit for a short to ground.
  15. Connect a test lamp between the control circuit terminal 85 and ground.
  16. Command the liftgate release actuator ON and OFF by pressing and releasing the liftgate release switch. The test lamp should turn ON and OFF while changing between the commanded states.
  17. If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the BCM.
    If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
  18. If all circuits test normal, test or replace the L/GATE RELSE relay.

Component Testing

Release Actuator, Door Latch - Liftgate

  1. Ignition OFF, disconnect the harness connector at the liftgate door latch.
  2. Install a 20A fused jumper wire between the control terminal 1 and 12 volts. Install a jumper wire between the ground terminal 3 and ground. Verify the release actuator activates.
  3. If the actuator does not perform as specified, replace the liftgate door latch.

Liftgate Release Switch

  1. Ignition OFF, disconnect the harness connector at the liftgate release switch.
  2. Test for infinite resistance between the signal terminal B and the ground terminal D with the switch in the open position.
  3. If not the specified value, replace the liftgate release switch.
  4. Test for less than 2 ohms between the signal terminal B and the ground terminal D with the switch in the closed position.
  5. If greater than the specified range, replace the liftgate release switch.

Relay Test

  1. Ignition OFF, disconnect the L/GATE RELSE relay.
  2. Test for 60-180 ohms between terminals 85 and 86.
  3. If not within the specified range, replace the relay.
  4. Test for infinite resistance between the following terminals:
  5. • 30 and 86
    • 30 and 87
    • 30 and 85
    • 85 and 87
    If not the specified value, replace the relay.
  6. Install a 20A fused jumper wire between relay terminal 85 and 12 volts. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.
  7. If greater than the specified range, replace the relay.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Relay Replacement
    •  Liftgate Outside Handle Replacement
    •  Liftgate Latch Replacement
    •  Control Module References for BCM replacement, setup and programming