For 1990-2009 cars

### 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 Lock and Window Switch B+ | 1, 2 | 1, 2 | -- | --
Driver Door Unlock Control | -- | 2, 3 | -- | --
All Door Lock Control | B3152 | 2, 3 | -- | --
Driver Door Lock Actuator Control | 4, 5, 6 | 4 | 4 | --
Passenger Door Lock Actuator Control | 4, 5, 6 | 5 | 5 | --
Rear Door Lock Actuator Control | 4, 5, 6 | 6 | 6 | --
Driver Door Lock and Window Switch Ground | -- | 1, 2 | 1, 2 | --
1. Driver Door Lock Switch Malfunction 2. Passenger Door Lock Switch Malfunction 3. Key Fob Malfunction 4. Driver Door Lock Malfunction 5. Passenger Door Lock Malfunction

6. Rear Door Lock Malfunction

### Circuit/System Description

When the driver switch assembly detects a transition of either its own door lock switch, the passenger door lock switch or the key cylinder switch to the LOCK position, it switches the door lock actuator lock control circuit to voltage. Since the lock actuator unlock control circuits are at ground potential within the driver switch assembly, the door lock actuator motors transition to the LOCK position.

When the driver switch assembly detects a transition of either its own door lock switch, the passenger door lock switch or the key cylinder switch to the UNLOCK position, it switches the driver door lock actuator unlock control circuit to voltage. Since the door lock actuator lock control circuit is at ground potential within the driver switch assembly, the LF door lock actuator motor transitions to the UNLOCK position.

When the driver switch assembly detects a transition of either its own door lock switch, the passenger door lock switch, or the key cylinder switch to the UNLOCK position, it switches the door lock actuator unlock control circuits to voltage. Since the door lock actuator lock control circuit is at ground potential within the driver switch assembly, the passenger door lock actuator motors transition to the UNLOCK position.

### 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

Ignition ON, command the doors to LOCK and UNLOCK while using the driver door lock switch and passenger door lock switch, all doors should perform the LOCK and UNLOCK function.

⇒ | If one or both door switches malfunction, refer to Lock Switch Malfunction.

⇒ | If one or more doors do not perform the LOCK or UNLOCK function, refer to Door Lock Actuator Malfunction.

### Circuit/System Testing

#### Lock Switch Malfunction

1. Ignition OFF, disconnect the X1 harness connector at the driver door lock switch.
2. Test for less than 1 ohm between the ground circuit terminal 3 and ground.

⇒ | If greater than the specified range, test the ground circuit for an open/high resistance.

3. Ignition ON, verify that a test lamp illuminates between the B+ circuit terminal 1 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance.

4. Connect the X1 harness connector and disconnect the X2 harness connector at the driver door lock switch.
5. Connect a test lamp between the control circuit terminal 13 and B+.
6. Command the Driver Door Unlock with a scan tool. The test lamp should illuminate during the UNLOCK command.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always ON, test the control circuit terminal for a short to ground. If the circuit tests normal, replace the BCM.

7. Connect a test lamp between the control circuit terminal 6 and B+.
8. Command the doors to UNLOCK by using the passenger door lock switch. The test lamp should illuminate during the UNLOCK command.

⇒ | If the test lamp is always OFF, replace the passenger door lock switch.

⇒ | If the test lamp is always ON, replace the passenger door lock switch.

9. Ignition OFF, disconnect the X1 harness connector at the BCM.
10. Connect a test lamp between the control circuit terminal 7 at the driver door lock switch and B+.
11. Ignition ON, command the doors to LOCK by using the passenger door lock switch. The test lamp should illuminate during the LOCK command.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the passenger door lock switch.

⇒ | If the test lamp is alwasy ON, test the control circuit terminal for a short to ground. If the circuit tests normal, replace the passenger door lock switch.

12. Ignition OFF, connect the X1 harness connector at the BCM.
13. Command the Lock All Doors with a scan tool. The test lamp should illuminate during the LOCK command.

⇒ | If the test lamp is always OFF, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.

⇒ | If the test lamp is always ON, test the control circuit terminal for a short to ground. If the circuit tests normal, replace the BCM.

14. If all circuits test normal, replace the driver door lock switch.

#### Door Lock Actuator Malfunction

1. Ignition OFF, disconnect the harness connector at the appropriate door lock actuator.
2. Test for less than 1 ohm between the control circuit terminal listed below and ground:

• | Control circuit terminal 1

• | Control circuit terminal 2

⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If circuits test normal, replace the driver door lock switch.

3. Connect a test lamp between the control circuit terminal 2 and control circuit terminal 3.
4. Ignition ON, command the door lock actuator to LOCK and UNLOCK by using the driver door lock switch. The test lamp should briefly illuminate when commanding the LOCK and UNLOCK states.

⇒ | If the test lamp does not illuminate during either of the commands, test either control circuit for a short to ground. If the circuits test normal, replace the driver door lock switch.

5. If all circuits test normal, test or replace the door lock actuator.

### Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate door lock actuator
2. Install a 15A fused jumper wire between the control terminal 1 and 12 volts. Momentarily install a jumper wire between the control terminal 2 and ground. The door lock actuator should perform the LOCK or UNLOCK function.

⇒ | If the function does not perform as specified, replace the door lock actuator.

3. Reverse the jumper wires; the door lock actuator should perform the UNLOCK or LOCK function.

⇒ | If the function does not perform as specified, replace the door lock actuator.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear Door Lock Replacement

• | Door Lock Switch Replacement - Driver Door

• | Door Lock Switch Replacement - Passenger Front

• | Front Side Door Lock Replacement

• | Control Module References for BCM replacement, setup, and programming