Operation CHARM: Car repair manuals for everyone.
Home >> Buick >> 2011 >> LaCrosse FWD V6-3.6L >> Repair and Diagnosis >> Lighting and Horns >> Testing and Inspection >> Symptom Related Diagnostic Procedures >> 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

The park lamps, tail lamps and license plate lights are turned ON when the headlamp switch is placed in the PARK 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 voltage on the control circuit, which illuminates the park lamps, tail lamps and license plate lights.

Reference Information
Schematic Reference

Exterior Lights Schematics (Exterior Lights Schematics)
Connector End View Reference

Component Connector End Views (Connector End Views By Name)
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 (Programming and Relearning) for scan tool information

Circuit/System Verification

1. Ignition ON, observe the function of the E2LF side marker lamp-left front and the E2LR side marker lamp-left rear while commanding the Left Park Lamps ON and OFF with a scan tool. The E2LF side marker lamp-left front and the E2LR side marker lamp-left rear should turn ON and OFF while changing between the commanded states

• If the E2LF side marker lamp-left front and the E2LR side marker lamp-left are always ON or always OFF, refer to Left Side Marker Lamps Malfunction.

2. Ignition ON, observe the function of the E2RF side marker lamp-right front and the E2RR side marker lamp-right rear while commanding the Right Park Lamps ON and OFF with a scan tool. The E2RF side marker lamp-right front and the E2RR side marker lamp-right rear should turn ON and OFF while changing between the commanded states.

• If the E2RF side marker lamp-right front and the E2RR side marker lamp-right are always ON or always OFF, refer to Right Side Marker Lamps Malfunction.

3. Observe the function of the E7L license plate lamp-left and E7R license plate lamp-right while commanding the license plate lamps ON and OFF with a scan tool. The E7L license plate lamp-left and E7R license plate lamp-right should turn ON and OFF when changing between the commanded states

• If the E7L license plate lamp-left or E7R license plate lamp-right is always OFF, inspect for a burned out bulb or corrosion of the bulb sockets.
• If the E7L license plate lamp-left and E7R license plate lamp-right are always OFF or always ON, refer to License Plate Lamp Malfunction.

Circuit/System Testing

Left Side Marker Lamps Malfunction
1. Ignition OFF, disconnect the X409 inline connector at the E5E tail lamp-left.
2. Disconnect the harness connector at the E2LF side marker lamp-left front.
3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Ignition ON, command the Left Park Lamps 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 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 BCM.

5. Ignition OFF, connect the harness connector at the E2LF side marker lamp-left front.
6. Ignition ON, command the Left Park Lamps ON and OFF with a scan tool. The E2LF side marker lamp-left front should turn ON and OFF when changing between the commanded states.

• If the E2LF side marker lamp-left front is always OFF, replace the E2LF side marker lamp-left front.

7. If all the circuits test normal, replace the E5E tail lamp-left.

Right Side Marker Lamps Malfunction
1. Ignition OFF, disconnect the X410 inline connector at the E5F tail lamp-right.
2. Disconnect the harness connector at the E2RF side marker lamp-right front.
3. Connect a test lamp between the control circuit terminal 1 and ground.
4. Ignition ON, command the Right Park Lamps 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 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 BCM.

5. Ignition OFF, connect the harness connector at the E2RF side marker lamp-right front.
6. Ignition ON, command the Right Park Lamps ON and OFF with a scan tool. The E2RF side marker lamp-right front should turn ON and OFF when changing between the commanded states.

• If the E2RF side marker lamp-right front is always OFF, replace the E2RF side marker lamp-right front.

7. If all the circuits test normal, replace the E5E tail lamp-right.

License Plate Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the E7L license plate lamp-left
2. Ignition OFF, disconnect the harness connector at the E7R license plate lamp-right
3. Test for less than 30 ohm between the ground circuit terminal 2 and ground.

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

4. Connect a test lamp between the control circuit terminal 1 and ground.
5. Ignition ON, command the license plate lamps ON and OFF with a scan tool. The test lamp should turn ON and OFF when changing between the selected 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 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 BCM.

6. If all circuits test normal, test or replace the E7L license plate lamp-left and E7R license plate lamp-right.

Repair Instructions

Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.

* Tail Lamp Replacement (Service and Repair)
* Front Turn Signal Lamp Bulb Replacement (TT2) (Front Turn Signal Lamp Bulb Replacement (TT2))Front Turn Signal Lamp Bulb Replacement (TT4) (Front Turn Signal Lamp Bulb Replacement (TT4))
* Rear License Plate Lamp Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, programming and setup

pro multis · About Operation CHARM