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

Left Front Door Ajar Switch Signal

B2976 00

2

2

--

Left Rear Door Ajar Switch Signal

B2996 00

2

2

--

Right Front Door Ajar Switch Signal

B2991 00

2

2

--

Right Rear Door Ajar Switch Signal

B3001 00

2

2

--

Cargo Door Ajar Switch Signal

1

2

2

--

Driver Door Latch Ground

--

2

2

--

LR Door Jamb Switch Ground

--

2

2

--

Front Passenger Door Latch Ground

--

2

2

--

RR Door Jamb Switch Ground

--

2

2

--

Cargo Door Latch Ground

--

2

2

--

1. Door Ajar Indicator Always Illuminated

2. Door Ajar Indicator Inoperative

Circuit/System Description

The body control module (BCM) monitors each door ajar circuit to indicate the status of the door. When the respective door is opened, the door ajar signal circuit is switched to ground by the door lock ajar indicator switch, the BCM detects the drop in voltage in the circuit and then communicates this status to the instrument panel cluster (IPC) via a serial data message. The IPC, upon receipt of this serial data message, will illuminate the appropriate ajar message in the driver information center (DIC) and when the transmission is shifted out of PARK, the DIC will also send a serial data message to the radio to activate the door ajar audible warning.

Reference Information

Schematic Reference

Door Lock/Indicator 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 Ajar Sw and Passenger Door Ajar Sw, parameters while opening and closing the driver and front passenger doors. The parameters should change between Door Closed and Door Ajar.
  2. If the parameters do not change while opening and closing the doors, refer to Front Door Ajar Malfunction.
  3. Observe the DIC message while opening and closing the left rear and right rear doors. The message should display Left Rear Door Open or Right Rear Door Open when the doors are open and should not display when the doors are closed.
  4. If the DIC message does not display when the doors are open or continuously displays when the doors are closed, refer to Rear Door Ajar Malfunction.

Circuit/System Testing

Front Door Ajar Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Test for less than 1 ohm between the ground circuit terminal listed below and ground.
  3. • Driver door latch ground circuit terminal D
    • Passenger door latch ground circuit terminal A
    If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Door Ajar Switch parameter is 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 BCM.
    • Driver door latch signal circuit terminal B
    • Passenger door latch signal circuit terminal C
  6. Install a 3A fused jumper wire between the signal circuit terminal and the ground circuit terminal listed below:
  7. • Driver door latch terminals B and D
    • Passenger door latch terminals C and A
  8. Verify the scan tool Door Ajar Switch parameter is Door Ajar.
  9. 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.
  10. If all circuits test normal, test or replace the door latch.

Rear Door Ajar Malfunction

  1. Ignition OFF, disconnect the harness connector at the appropriate door jamb switch.
  2. Test for less than 1 ohm between the ground circuit terminal A and ground.
  3. If greater than the specified range, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the DIC Door Open message is not displayed.
  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 the ground circuit terminal A. Verify the DIC Door Open message is displayed
  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 door jamb switch.

Component Testing

Front Door Latch

  1. Ignition OFF, disconnect the harness connector at the appropriate door latch.
  2. Test for infinite resistance between the signal terminal and the ground terminal listed below with the door latch in the open position.
  3. • Driver door latch terminal B and D
    • Passenger door latch terminal C and A
    If not the specified value, replace the door latch.
  4. Test for less than 2 ohms between the signal terminal and the ground terminal listed below with the door latch in the closed position;
  5. • Driver door latch terminal B and D
    • Passenger door latch terminal C and A
    If greater than the specified range, replace the door latch.

Door Jam Switch

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

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Front Side Door Window Module Replacement
    •  Control Module References for BCM replacement, setup and programming