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

Ratchet Switch Signal

2

B153A 08

1

--

1. Liftgate Ajar Indicator Inoperative

2. Liftgate Ajar Indicator Always ON

Circuit/System Description

The driver information center (DIC) illuminates the LIFT GATE AJAR indicator when the liftgate module (LGM) detects the liftgate ratchet switch is closed to ground indicating the liftgate is open. The instrument panel cluster receives a serial data message from the LGM indicating the liftgate ajar status. If this message is displayed and the vehicle speed is greater than 8 km/h (5 mph), a chime will sound.

Reference Information

Schematic Reference

Liftgate Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Liftgate Description and Operation

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, observe the scan tool LGM Latch Ratchet Sw. parameter while opening and closing the liftgate. The parameter should change between Active and Inactive.

Circuit/System Testing

  1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
  2. Ignition ON, verify the scan tool LGM Latch Ratchet Sw. parameter is Inactive.
  3. If not the specified value, test the signal circuit terminal 6 for a short to ground. If the circuit tests normal, replace the LGM.
  4. Install a 3A fused jumper wire between the signal circuit terminal 6 and ground. Verify the scan tool LGM Latch Ratchet Sw. parameter is Active.
  5. 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 LGM
  6. If all circuits test normal, test or replace the liftgate latch assembly.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Control Module References for LGM replacement, setup, and programming