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 Ajar Switch Signal

1

2

2

--

Liftgate Ajar Switch Signal

1

2

2

--

Door Lock Ground

--

2

2

--

Liftgate Latch Ground

--

2

2

--

1. Door Ajar Indicator Always Illuminated

2. Door Ajar Indicator Malfunction

Circuit/System Description

The door ajar and liftgate ajar switches supply a ground to the rear fuse block when the door is open. Once the door or liftgate is closed the door ajar switch opens removing the ground to the rear fuse block. The rear fuse block sends a signal to the instrument panel cluster (IPC) to illuminate the door ajar indicator when a door or liftgate is open.

Reference Information

Schematic Reference

    •  Door Lock/Indicator Schematics
    •  Release Systems Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Door Ajar Indicator 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

  1. Ignition ON, observe the scan tool Driver Door Status, Passenger Door Status, Rear Left Door Status and Rear Right Door Status parameters while opening and closing each door. The parameters should change from Door Closed to Door Open while opening and closing the doors.
  2. If the value does not change, refer to Door Ajar Malfunction.
  3. Observe the Trunk Status parameter while opening and closing the liftgate. The parameter should change from Trunk Closed to Trunk Open while opening and closing the liftgate
  4. If the value does not change, refer to Liftgate Ajar Malfunction.

Circuit/System Testing

Door Ajar Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate door lock.
  2. Test for less than 1 ohm between the ground circuit terminal listed below and ground:
  3. • Driver door lock terminal 7
    • Passenger door lock terminal 7
    • Left rear door lock terminal 4
    • Right rear door lock terminal 4
    If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Driver Door Status, Passenger Door Status, Rear Left Door Status and Rear Right Door Status parameters are Door Closed.
  5. If not the specified value, test the signal circuit terminal listed below for a short to ground. If the circuit tests normal, replace the rear fuse block.
    • Driver door lock terminal 6
    • Passenger door lock terminal 6
    • Left rear door lock terminal 5
    • Right rear door lock terminal 5
  6. Install a 3A fused jumper wire between the signal circuit terminal listed below and ground. Verify the scan tool Driver Door Status, Passenger Door Status, Rear Left Door Status and Rear Right Door Status parameters are Door Open.
  7. • Driver door lock terminal 6
    • Passenger door lock terminal 6
    • Left rear door lock terminal 5
    • Right rear door lock terminal 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 rear fuse block.
  8. If all circuits test normal, test or replace the door lock.

Liftgate Ajar Malfunction

  1. Ignition OFF, disconnect the harness connector at the liftgate latch assembly.
  2. Ignition ON, verify the scan tool Trunk Status parameter is Trunk Closed.
  3. If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the rear fuse block.
  4. Install a 3A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 2. Verify the scan tool Trunk Status parameter is Trunk Open.
  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 rear fuse block.
  6. If all circuits test normal, test or replace the liftgate latch assembly.

Component Testing

Door Lock

  1. Ignition OFF, disconnect the harness connector at the appropriate door lock.
  2. Test for infinite resistance between the signal terminal and the ground terminal listed below with the door lock in the open position.
  3. • Driver door lock signal terminal 6 and ground terminal 7
    • Passenger door lock signal terminal 6 and ground terminal 7
    • Left rear door lock signal terminal 5 and ground terminal 4
    • Right rear door lock signal terminal 5 and ground terminal 4
    If not the specified value, replace the door lock.
  4. Test for less than 2 ohms between the signal terminal and the ground terminal listed below with the door lock in the closed position.
  5. • Driver door lock signal terminal 6 and ground terminal 7
    • Passenger door lock signal terminal 6 and ground terminal 7
    • Left rear door lock signal terminal 5 and ground terminal 4
    • Right rear door lock signal terminal 5 and ground terminal 4
    If greater than the specified range, replace the door lock.

Liftgate Latch Assembly

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Lock Replacement
    •  Rear Door Lock Replacement
    •  Liftgate Latch Replacement
    •  Control Module References for rear fuse block replacement, setup, and programming