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Home >> Buick >> 2013 >> Verano L4-2.0L Turbo >> Repair and Diagnosis >> Lighting and Horns >> Testing and Inspection >> Park, License, and/or Tail Lamps Malfunction

Park, License, and/or Tail Lamps Malfunction




Park, License, and/or Tail Lamps Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

When the headlamp switch is placed in the HEAD or PARK position, ground is applied to the park lamp switch ON signal circuit to the body control module (BCM). The BCM responds by applying voltage to the park lamps, tail lamps, and license lamps control circuits illuminating the park, tail, and license lamps.

Reference Information

Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

Exterior Lighting Systems Description and Operation Exterior Lighting Systems

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information

Circuit/System Verification

1. Ignition ON.

2. Verify the scan tool Park Lamp Switch parameter changes between Active and Inactive while commanding the park lamps ON and OFF with the headlamp switch.

• If the parameter does not change
Refer to Park Lamp Switch Malfunction.

• If the parameter changes

3. Verify the left park lamps turn ON and OFF when commanding the Left Park Lamps ON and OFF with a scan tool.

• If the left park lamps do not turn ON and OFF
Refer to Park Lamps Malfunction.

• If the left park lamps turn ON and OFF

4. Verify the right park lamps turn ON and OFF when commanding the Right Park Lamps ON and OFF with a scan tool.

• If the right park lamps do not turn ON and OFF
Refer to Park Lamps Malfunction.

• If the right park lamps turn ON and OFF

5. Verify the license plate lamps turn ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.

• If the license plate lamps do not turn ON and OFF
Refer to License Plate Lamps Malfunction.

• If the license plate lamps turn ON and OFF

6. All OK.

Circuit/System Testing

Park Lamp Switch Malfunction

1. Ignition OFF, scan tool disconnected, all doors closed, all accessories OFF, disconnect the harness connector at the S30 headlamp switch. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 5 ohms between the ground circuit terminal 6 and ground.

• If 5 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 5 ohms

3. Ignition ON.

4. Verify the scan tool Park Lamps Switch parameter is Inactive.

• If not Inactive

1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module.

2. Test for infinite resistance between the signal circuit terminal 3 and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance, replace the K9 body control module.

• If Inactive

5. Install a 3 A fused jumper wire between the signal circuit terminal 3 and the ground circuit terminal 6.

6. Verify the scan tool Park Lamps Switch parameter is Active.

• If not Active

1. Ignition OFF, disconnect the X1 harness connector at the K9 body control module, ignition ON.

2. Test for less than 1 V between the signal circuit terminal 3 and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V

3. Test for less than 2 ohms in the signal circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If Active

7. Test or replace the S30 headlamp switch.

Park Lamps Malfunction

1. Ignition OFF, exterior lamps OFF, disconnect the harness connector at the appropriate park lamp.

2. Test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.

* E13LA headlamp assembly - left - terminal A

* E42L tail lamp assembly - left - terminal A

* E58L rear compartment lid lamp assembly - left - terminal A

* E13RA headlamp assembly - right - terminal A

* E42R tail lamp assembly - right - terminal A

* E58R rear compartment lid lamp assembly - right - terminal A

• If 5 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 5 ohms

3. Connect a test lamp between the appropriate control circuit terminal listed below and ground, ignition ON.

* E13LA headlamp assembly - left - terminal D

* E42L tail lamp assembly - left - terminal C

* E58L rear compartment lid lamp assembly - left - terminal B

* E13RA headlamp assembly - right - terminal D

* E42R tail lamp assembly - right - terminal C

* E58R rear compartment lid lamp assembly - right - terminal B

4. Verify the test lamp turns ON and OFF when commanding the appropriate Park Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON.

2. Test for less than 1 V between the control circuit terminal and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K9 body control module.

• If the test lamp turns ON and OFF

5. Test or replace the appropriate park lamp.

License Plate Lamps Malfunction

1. Ignition OFF, exterior lamps OFF, remove both E7 license plate lamp bulbs.

2. Test for less than 5 ohms between each ground circuit terminal 2 and ground.

• If 5 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 5 ohms

3. Connect a test lamp between the license plate lamp - left control circuit terminal 1 and ground, ignition ON.

4. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If the test lamp is always ON

1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module, ignition ON.

2. Test for less than 1 V between the control circuit terminal and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the K9 body control module.

• If the test lamp turns ON and OFF

5. Connect a test lamp between the license plate lamp - right control circuit terminal 1 and ground, ignition ON.

6. Verify the test lamp turns ON and OFF when commanding the License Plate Lamps ON and OFF with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, disconnect the X4 harness connector at the K9 body control module.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the K9 body control module.

• If the test lamp turns ON and OFF

7. Test or replace the appropriate E7 license plate lamp bulb.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

* Tail Lamp Bulb Replacement Service and Repair

* Front Position Lamp Bulb Replacement Front Position Lamp Bulb Replacement

* Rear License Plate Lamp Replacement Rear License Plate Lamp Replacement

* Headlamp Switch Replacement Service and Repair

* Control Module References Control Module References for BCM replacement, programming, and setup

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