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 the diagnostic category.

### Diagnostic Fault Information

Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance
--- | --- | --- | --- | ---
Door Lock Relay B+ | B004A 00 | 4 | -- | --
Door Unlock Relay B+ | B004A 00 | 4 | -- | --
Central Door Lock Switch Lock/Unlock Signal | B3150 5A | 1 | 1 | --
Door Lock Relay Control | 2 | B004A 00 | 4 | --
Door Lock Indicator Control | 3 | 3 | 3 | --
Door Unlock Relay Control | 2 | B004A 00 | 4 | --
Lock Control | 2 | 2 | 2 | --
Unlock Control | 2 | 2 | 2 | --
Door Lock Relay Ground | -- | 4 | 4 | --
Door Unlock Relay Ground | -- | 4 | 4 | --
Multifunction I/P Switch Ground | -- | 1,3 | 1,3 | --
1. Central Door Lock Switch Inoperative 2. Door Locks Inoperative 3. Door Lock Indicator Malfunction 4. Crash Unlock Malfunction

### Circuit/System Description

The rear fuse block monitors the voltage in the central door lock switch signal circuit, when the central door lock switch is pressed, the voltage drops below 1 volt and the rear fuse block will apply voltage to the lock relay and ground to the unlock relay, which will cause the door locks to LOCK.

When the door central door lock switch is pressed again, the central door lock switch signal circuit will be open and the voltage will be at or near 9 volts and the rear fuse block will apply voltage to the unlock relay and ground to the lock relay, which will cause the door locks to UNLOCK.

### Diagnostic Aids

Verify the driver door is closed, the central door lock switch is disabled when the driver door is in the open or ajar position. If the driver door is closed and the door ajar light is illuminated, refer to Door Ajar Indicator Malfunction.

### 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 CDLS Switch Status parameter while using the central door lock switch. The parameter should briefly change from Off to On.

⇒ | If the value is always On or always Off, refer to Door Lock Switch Malfunction.

2. Command the CDL/ATWS Telltail Test ON and OFF with a scan tool, the door lock indicator should turn ON and OFF when changing between the commanded states.

⇒ | If the indicator is always ON or always OFF, refer to Door Lock Switch Indicator Malfunction.

3. Command the Unlock/Lock Test to LOCK and UNLOCK with a scan tool, all doors should LOCK and UNLOCK.

⇒ | If any or all doors do not LOCK and UNLOCK when changing between commanded states, refer to Door Lock Malfunction.

### Circuit/System Testing

#### Door Lock Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P multifunction switch.
2. Ignition ON, verify the scan tool CDLS Switch Status parameter is Off.

⇒ | If not the specified value, test the signal circuit terminal 5 for a short to ground. If the circuit tests normal, replace the instrument panel cluster.

3. Connect a 3A fused jumper wire between the signal circuit terminal 5 and ground, verify the CDLS Switch Status parameter is On.

⇒ | If not the specified value, test the signal circuit for a short to voltage or and open/high resistance. If the circuit tests normal, replace the instrument panel cluster.

4. If all circuits test normal, test or replace the I/P multifunction switch.

#### Door Lock Switch Indicator Malfunction

1. Ignition OFF, disconnect the harness connector at the I/P multifunction switch.
2. Ignition ON, test for greater than 9V between the control circuit terminal 14 and ground while commanding the CDL/ATWS Telltail Test ON with a scan tool.

⇒ | If less than the specified range, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the rear fuse block.

3. Test for less than 1V between the control circuit terminal 14 and ground while commanding the CDL/ATWS Telltail Test OFF with a scan tool.

⇒ | If greater than the specified range, test the control circuit for a short to voltage. If the circuit tests normal, replace the rear fuse block.

4. If all circuits test normal, replace the I/P multifunction switch.

#### Door Lock Malfunction

1. Ignition OFF, disconnect the Door Lock relay.
2. Test for less than 5 ohms between the control circuit terminal 4 and ground.

⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the rear fuse block.

3. Verify that a test lamp does not illuminate between the control circuit terminal 2 and B+.

⇒ | If the test lamp illuminates, test the control circuit for a short to ground. If the circuit tests normal, replace the underhood fuse block.

4. Connect a test lamp between the control circuit terminal 4 and ground.
5. Ignition ON, command the Unlock/Lock Test with a scan tool, the test lamp should briefly illuminate when changing between the commanded states.

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground. If the circuit tests normal, replace the rear fuse block.

6. Ignition OFF, disconnect the Door Unlock relay.
7. Test for less than 5 ohms between the control circuit terminal 4 and ground.

⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the rear fuse block.

8. Verify that a test lamp does not illuminate between the control circuit terminal 2 and B+.

⇒ | If the test lamp illuminates, test the control circuit for a short to ground.

9. Connect a test lamp between the control circuit terminal 4 and ground.
10. Ignition ON, command the Unlock/Lock Test with a scan tool, the test lamp should briefly illuminate when changing between the commanded states.

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground. If the circuit tests normal, replace the rear fuse block.

11. Ignition OFF, connect the Door Lock and Door Unlock relays and disconnect the appropriate door lock.
12. Test for less than 5 ohms between the control circuit terminal listed below and ground:

• | Driver door lock terminal 8

• | Passenger door lock terminal 8

• | Left rear door lock terminal 6

• | Right rear door lock terminal 6

⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the Door Unlock relay.

13. Test for less than 5 ohms between the control circuit terminal 2 and ground.

⇒ | If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the Door Lock relay

14. Ignition ON, connect a test lamp between the control circuit listed below and ground:

• | Driver door lock terminal 8

• | Passenger door lock terminal 8

• | Left rear door lock terminal 6

• | Right rear door lock terminal 6

15. Command the Unlock/Lock Test to LOCK and UNLOCK with a scan tool, the test lamp should briefly illuminate when changing between the commanded states.

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground. If the circuit tests normal, replace the Door Unlock relay.

16. Connect a test lamp between the control circuit terminal 2 and ground.
17. Command the Unlock/Lock Test to LOCK and UNLOCK with a scan tool, the test lamp should briefly illuminate when changing between the commanded states.

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground. If the circuit tests normal, replace the Door Lock relay.

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

### Component Testing

1. Ignition OFF, disconnect the harness connector at the appropriate door lock.
2. Install a 7.5A fused jumper wire between one of the control terminals and 12V. Momentarily install a jumper wire between the other control terminal and ground. Reverse the jumper wires at least two times, the door lock should perform the LOCK/UNLOCK functions.

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

#### Relay Test

1. Ignition OFF, disconnect the appropriate relay.
2. Test for 60-200 ohms between terminals 85 and 86.

⇒ | If not within the specified range, replace the relay.

3. Test for infinite resistance between the following terminals:

• | 30 and 86

• | 30 and 87

• | 30 and 85

• | 85 and 87

⇒ | If less than the specified value, replace the relay.

4. Test for less than 2 ohms between terminals 30 and 87A.

⇒ | If greater than the specified range, replace the relay.

5. Install a 3-amp fused jumper wire between the relay terminal 85 and 12V. Install a jumper wire between relay terminal 86 and ground. Test for less than 2 ohms between terminals 30 and 87.

⇒ | If greater than specified range, replace the relay.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Front Side Door Lock Replacement

• | Accessory Switch Replacement

• | Relay Replacement

• | Rear Door Lock Replacement

• | Control Module References for rear fuse block, instrument panel cluster and underhood fuse block replacement, setup, and programming