For 1990-2009 cars

### Circuit Description

The front passenger door lock switch is wired to the PDM. The lock switch receives a constant ground source. There are 2 signal circuits, one for lock signal, and one for unlock signal. When the switch is activated for a lock or unlock function, the normally open switch contacts for that function are closed and provide a switched ground signal to the PDM.

The driver door lock switch is wired to the DDSA. The lock switch receives a constant ground source. There are 2 signal circuits, one for lock signal, and one for unlock signal. When the switch is activated for a lock or unlock function, the normally open switch contacts for that function are closed and provide a switched ground signal to the DDSA. These switch activations are detected and processed by the DDSA and then communicated to the DDM via a GMLAN message. For more detailed information concerning power door lock operation refer to Power Door Locks Description and Operation .

### DTC Descriptors

This diagnostic procedure supports the following DTCs:

• | DTC B3140 Unlock Switch Circuit

• | DTC B3150 Lock Switch Circuit

This vehicle has DTCs which include DTC symptoms. For more information on DTC symptoms, refer to DTC Symptom Description .

DTC Symptom | DTC Symptom Descriptor
--- | ---
02 | Short to Ground

### Conditions for Running the DTC

• | The PDM and the DDSA must be powered.

• | DTC B1325 Battery Voltage Out of Range, must not be current.

### Conditions for Setting the DTC

The DDSA detects that either the Lock or Unlock switch is closed for more than 30 continuous seconds.

### Action Taken When the DTC Sets

The DDSA and PDM ignores inputs from the Lock/Unlock switch.

### Conditions for Clearing the DTC

• | The condition responsible for setting the DTC no longer exists.

• | You issue a scan tool CLEAR DTCs command.

• | After 40 consecutive warm-up cycles without failure, the history DTC will be cleared.

### Diagnostic Aids

Thoroughly inspect the wiring and connectors. An incomplete inspection of the wiring and connectors may result in misdiagnosis causing part replacement with the reappearance of the malfunction. If an intermittent malfunction exists, refer to Testing for Intermittent Conditions and Poor Connections .

Step | Action | Yes | No
--- | --- | --- | ---
Schematic Reference: Door Lock/Indicator Schematics Connector End View Reference: Vehicle Access Connector End Views
1 | Did you perform the Diagnostic System Check - Vehicle? | Go to Step 2 | Go to Diagnostic System Check - Vehicle
2 |

1. Install a scan tool.
2. Turn ON the ignition, with the engine OFF.
3. With the scan tool, observe the suspect Door Lock Switch parameter in the appropriate data list:

• | Driver Door Switch Assembly (DDSA)

• | Passenger Front Door Module (PDM)

Does the scan tool display Idle?

Go to Step 3

Go to Step 4

3 |

1. Activate the associated door lock switch.
2. With the scan tool, observe the appropriate Door Lock Switch parameter.

Does the Door Lock Switch parameter change state?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 4

4 |

1. Turn OFF the ignition.
2. Disconnect the associated door lock switch harness connector.
3. Turn ON the ignition with the engine OFF.
4. With the scan tool, observe the appropriate Door Lock Switch parameter.

Does the scan tool display Idle?

Go to Step 7

Go to Step 5

5 | Test the appropriate door lock switch signal circuit for a short to ground. Refer to Circuit Testing and Wiring Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 6
6 | Inspect for poor connections at the appropriate door control module harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 8
7 | Inspect for poor connections at the appropriate door lock switch harness connector. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs . Did you find and correct the condition? | Go to Step 10 | Go to Step 9
8 | Replace the appropriate door control module. Refer to Control Module References for replacement, setup and programming. Did you complete the replacement? | Go to Step 10 | --
9 | Replace the appropriate door lock switch. Refer to Door Lock and Side Window Switch Replacement - Driver Side . Did you complete the replacement? | Go to Step 10 | --
10 |

1. Use the scan tool in order to clear the DTCs.
2. Operate the vehicle within the Conditions for Running the DTC as specified in the supporting text.

Does the DTC reset?

Go to Step 2

System OK