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

Driver Door Latch Control

1

1

B2517

--

Driver Door Latch Enable Control

1

1

B2517

--

Front Passenger Door Latch Control

1

1

B2518

--

Front Passenger Door Latch Enable Control

1

1

B2518

--

Driver Door Lock Switch Lock Signal

B3152

2

2

--

Driver Door Lock Switch Unlock Signal

B3142

2

2

--

Left Front Exterior Door Handle Switch Signal

B3849

1

1

--

Left Front Interior Door Handle Switch Signal

B3848

1

1

--

Passenger Door Lock Switch Lock Signal

B3155

2

2

--

Passenger Door Lock Switch Unlock Signal

B3145

2

2

--

Right Front Exterior Door Handle Switch Signal

B1474

1

1

--

Right Front Interior Door Handle Switch Signal

B2981

1

1

--

Driver Exterior Door Handle Switch Ground

--

1

1

--

Driver Interior Door Handle Switch Ground

--

1

1

--

Passenger Exterior Door Handle Switch Ground

--

1

1

--

Passenger Interior Door Handle Switch Ground

--

1

1

--

Driver Door Lock Switch Ground

--

2

2

--

Passenger Door Lock Switch Ground

--

2

2

--

  1. Power Door Latch System Malfunction
  2. Power Door Locks Inoperative

Circuit/System Description

Driver Door Lock and Unlock Operation

The driver door lock switch lock and unlock signal circuits provide input to the driver window switch when the driver door lock switch is activated to the Lock or Unlock position. These inputs allow the driver window switch to detect a door lock or unlock request. The driver window switch provides power to the driver door lock switch. When the driver window switch detects low voltage on a signal circuit, the driver window switch will send a message on the serial data line to the remote control door lock receiver (RCDLR) to place the driver and passenger doors in lock or unlock status, disabling or enabling the power door latch.

Passenger Door Lock and Unlock Operation

The passenger door lock switch lock and unlock signal circuits provide input to the passenger door module (PDM) when the passenger door lock switch is activated to the Lock or Unlock position. These inputs allow the PDM to detect a door lock or unlock request. The PDM provides power to the passenger door lock switch. When the PDM detects low voltage on a signal circuit, the PDM will send a message on the serial data line to the remote control door lock receiver (RCDLR) to place the driver and passenger doors in lock or unlock status, disabling or enabling the power door latch.

Reference Information

Schematic Reference

Door Lock/Indicator Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Power Door Locks 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 Door Lock Switch parameter while using the driver door lock switch. The parameter should change from Idle to Lock and Unlock.
  2. If the valuedoes not change, refer to Driver Door Lock Switch Malfunction.
  3. Observe the scan tool Door Lock Switch parameter while using the passenger door lock switch. The parameter should change from Idle to Lock and Unlock.
  4. If the value does not change, refer to Passenger Door Lock Switch Malfunction.

Circuit/System Testing

Driver Door Lock Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the driver door lock switch.
  2. Verify that a test lamp illuminates between B+ and the ground circuit terminal C.
  3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Door Lock Switch parameter is Idle.
  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 driver window switch.
    • Signal circuit terminal D
    • Signal circuit terminal E
  6. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool Door Lock Switch parameter is Lock.
  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 driver window switch.
  8. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Door Lock Switch parameter is Unlock.
  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 driver window switch.
  10. If all circuits test normal, test or replace the driver door lock switch.

Passenger Door Lock Switch Malfunction

  1. Ignition OFF, disconnect the harness connector at the passenger door lock switch.
  2. Verify that a test lamp illuminates between B+ and the ground circuit terminal C.
  3. If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
  4. Ignition ON, verify the scan tool Door Lock Switch parameter is Idle.
  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 PDM.
    • Signal circuit terminal D
    • Signal circuit terminal E
  6. Install a 3A fused jumper wire between the signal circuit terminal D and ground. Verify the scan tool Door Lock Switch parameter is Lock.
  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 PDM.
  8. Install a 3A fused jumper wire between the signal circuit terminal E and ground. Verify the scan tool Door Lock Switch parameter is Unlock.
  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 PDM.
  10. If all circuits test normal, test or replace the passenger door lock switch.

Component Testing

  1. Ignition OFF, disconnect the harness connector at the appropriate door lock switch.
  2. Test for infinite resistance between the signal terminals D and E and the ground terminal C with the switch in the open position.
  3. If less than the specified value, replace the door lock switch.
  4. Test for less than 2 ohms between the signal terminal E and the ground terminal C with the switch in the unlock position.
  5. If greater than the specified range, replace the door lock switch.
  6. Test for less than 2 ohms between the signal terminal D and the ground terminal C with the switch in the lock position.
  7. If greater than the specified range, replace the door lock switch.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

    •  Door Lock Switch Replacement - Driver Door
    •  Door Lock Switch Replacement - Passenger Front
    •  Control Module References for Driver Door Switch Assembly and PDM replacement, setup, and programming