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
--- | --- | --- | --- | ---
Park Lamp Switch On Signal | B257A 00 | B257A 00 | B257A 00 | --
Left/Right Daytime Running Lamps (DRL) Relay Control | 1 | 2 | 2 | --
Left/Right Park Lamp Control | 2 | 2 | 1 | --
Number Plate Light Control | 2 | 2 | 1 | --
Park Lamps Ground | -- | 2 | -- | --
Number Plate Lights Ground | -- | 4 | -- | --
1. Park lamps always ON 2. Park lamps always OFF 3. Number plate lights always ON 4. Number plate lights always OFF

### Circuit/System Description

The park lamps, tail lamps and number plate lights are turned ON when the headlamp switch is placed in the PARKING LIGHT or LOW BEAM position or anytime the headlights are requested. When the body control module (BCM) receives a request from the headlamp switch to turn ON the park lamps the BCM a sends out a PWM signal, which illuminates the park lamps, tail lamps and number plate lights.

### Reference Information

#### Schematic Reference

Exterior Lights Schematics

#### Connector End View Reference

Component Connector End Views

#### Description and Operation

Exterior Lighting Systems 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. Command the park lamps ON and OFF using the headlamp switch. Verify the scan tool Park Lamp Switch parameter cycles between Active and Inactive as commanded.

⇒ | If the parameter does not cycle between the specified values, refer to Park Lamp Switch Malfunction.

2. Ignition ON, switch ON and OFF the park lamps and number plate lights by using the headlamp switch. Park lamps and number plate lights should go ON and OFF.

⇒ | If the park lamps are inoperative, refer to Park Lamps Inoperative

⇒ | If the number plate lights are inoperative, refer to Number Plate Lights Inoperative

### Circuit/System Testing

#### Park Lamp Switch Malfunction

1. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
2. Verify that a test lamp illuminates between the ground circuit terminal 6 and B+.

⇒ | If the test lamp does not illuminate, test the ground circuit for an open/high resistance.

3. Ignition ON, test for B+ between the park lamp signal circuit terminal 3 and ground.

⇒ | If less than the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).

4. Install a 3 A fused jumper wire between the park lamp ON signal circuit terminal 3 and ground. Verify the scan tool Parklamp Switch parameter changes from Inactive to Active.

⇒ | If always Inactive, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒ | If always active, test the signal circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).

5. If all circuits test normal, replace the S30 Headlamp Switch.

#### Park Lamps Inoperative - without high intensity discharge headlamps

1. Supply sufficient light to simulate daylight conditions to the ambient light sensor.
2. Ignition ON, headlamp switch in the AUTOMATIC LIGHT position.
3. Observe the headlamps. The headlamps should not be illuminated.

⇒ | If the headlamps are illuminated, replace the ambient light sensor.

4. Ignition OFF, disconnect the appropriate KR42L Daytime Running Lamp Relay - Left or KR42R Daytime Running Lamp Relay - Right.
5. Ignition ON, verify that a test lamp does not illuminate between the control circuit terminal 87 and ground.

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

6. Verify that a test lamp illuminates between the B+ circuit terminal 86 and ground.

⇒ | If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, test or replace the appropriate inoperative daytime running relay.

7. Verify that a test lamp illuminates between the B+ circuit terminal 30 and ground.

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

8. Connect a test lamp between the B+ circuit terminal 86 and the control circuit terminal 85.
9. Command the Left or Right Dedicated Daytime Running Lamp Command ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to ground. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒ | 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 K9 Body Control Module (BCM).

10. Connect a 10 A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87.
11. Disconnect the harness connector at one of the daytime running lamps.
12. Verify that a test lamp illuminates between the DRL control circuit terminal 9 and ground.

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

13. Verify that a test lamp illuminates between the DRL ground circuit terminal 1 and B+.

⇒ | If the test lamp does not illuminate, test the ground circuit for a open/high resistance.

14. If all circuits test normal, test or replace the appropriate inoperative daytime running lamp or relay.

#### Park Lamps Inoperative - with high intensity discharge headlamps

1. Supply sufficient light to simulate daylight conditions to the ambient light sensor.
2. Ignition ON, headlamp switch in the AUTOMATIC LIGHT position.
3. Observe the park lamps. The park lamps should not be illuminated.

⇒ | If the park lamps are illuminated, replace the ambient light sensor.

4. Ignition OFF, disconnect the harness connector of the appropriate inoperative headlamp.
5. Connect a test lamp between the DRL control circuit terminal 4 and ground.
6. Command the Left or Right Dedicated Daytime Running Lamp Command ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the commanded states.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the K9 Body Control Module (BCM).

7. Verify that a test lamp illuminates between the DRL ground circuit terminal 1 and B+.

⇒ | If the test lamp does not illuminate, test the ground circuit for a open/high resistance.

8. If all circuits test normal, test or replace the appropriate inoperative daytime running lamp.

#### Number Plate Lights Inoperative

1. Ignition OFF, disconnect the harness connector X5 at the K9 Body Control Module (BCM).
2. Verify that a test lamp illuminates between the voltage supply circuit terminal 4 (X5) and ground.

⇒ | If the test lamp does not illuminate, test the cornering lamp voltage supply circuit for open/high resistance or short to ground. If the circuit tests normal, replace K9 Body Control Module (BCM).

3. Ignition OFF, disconnect the harness connector at the appropriate park lamp.
4. Test for less than 5 Ω between the appropriate inoperative number plate light ground circuit terminal 2 and ground.

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

5. Connect a test lamp between the appropriate inoperative control circuit terminal 1 and ground.
6. Switch ON the parking lamps or low beam. The test lamp should be ON.

⇒ | If the test lamp is always ON, test the control circuit for a short to voltage. If the circuit tests normal, replace the K9 Body Control Module (BCM).

⇒ | If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance. If the circuits test normal, replace the K9 Body Control Module (BCM).

7. If all the circuits test normal, replace the appropriate inoperative number plate light.

### Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

• | Rear License Lamp Replacement

• | License Lamp Bulb Replacement

• | Headlamp Replacement

• | Headlamp Bulb Replacement

• | Headlamp Switch Replacement

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