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Home >> Saturn >> 2008 >> Astra L4-1.8L >> 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 (Initial Inspection and Diagnostic Overview) prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis (Initial Inspection and Diagnostic Overview) for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions (Initial Inspection and Diagnostic Overview) provides an overview of each diagnostic category.



Diagnostic Fault Information






Circuit/System Description

The headlamp switch is supplied with voltage from the instrument panel cluster (IPC) by two signal circuits, the AUTO lamps signal circuit and the PARK lamp signal circuit. When the headlamp switch is placed in the PARK position, the park lamp signal circuit is provided with ground through the switch contacts of the park lamp switch to a common headlamp switch ground back to the IPC. The IPC interprets the flow of voltage and responds by sending a serial data message to the underhood electrical center (UEC) and the rear electrical center (REC) requesting the front and rear park lamps be activated. The UEC and REC respond by applying voltage to there respective park, marker, and license lamp control circuits illuminating the park, marker and license lamps.


Reference Information
Schematic Reference

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

Component Connector End Views (Connector Views)
Description and Operation

Exterior Lighting Systems Description and Operation (Exterior Lighting Systems Description and Operation)
Electrical Information Reference

* Circuit Testing (Component Tests and General Diagnostics)
* Connector Repairs (Component Tests and General Diagnostics)
* Testing for Intermittent Conditions and Poor Connections (Component Tests and General Diagnostics)
* Wiring Repairs (Component Tests and General Diagnostics)

Scan Tool Reference

Control Module References (Programming and Relearning) for scan tool information


Circuit/System Verification

1. Ignition ON, observe the scan tool Parking Light Status parameter while cycling the park lamp switch ON and OFF. The readings should toggle between ON and OFF.

• If the readings do not change between the commanded states, refer to Park Lamp Switch Malfunction.

2. Command the Front Parking Light Test ON and OFF with a scan tool. The front park lamps should turn ON and OFF when commanded.

• If the front park lamps do not illuminate when commanded, refer to Front Park Lamps Malfunction.

3. Command the Rear Outer Combination Lamps Test ON and OFF with a scan tool. The rear park lamps should turn ON and OFF when commanded.

• If the rear park lamps do not illuminate when commanded, refer to Rear Park Lamps Malfunction.

4. Command the License Plate Light Test ON and OFF with a scan tool. The license lamps should turn ON and OFF when commanded.

• If the license lamps do not illuminate when commanded, refer to License Lamps Malfunction.

5. Command the Rear Side Markers Test ON and OFF with a scan tool. The front and rear side marker lamps should turn ON and OFF when commanded.

• If the front and rear side marker lamps do not illuminate when commanded, refer to Side Marker Lamps Malfunction.




Circuit/System Testing


Park Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition OFF, verify a test lamp illuminates between B+ and the ground circuit terminal 11.

• If the test lamp does not illuminate, test the ground circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.

3. Ignition ON, park lamps ON, verify the scan tool Parking Light Status parameter is OFF.

• If not the specified value, test the signal circuit terminal 2 for a short to ground. If the circuit tests normal, replace the IPC.

4. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Parking Light Status parameter is ON.

• If not the specified value, test the signal circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the IPC.

5. If all circuits test normal, replace the headlamp switch.



Front Park Lamps Malfunction
1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 4 and ground.
4. Command the Front Parking Light Test 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 UEC.
• 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 UEC.

5. If all circuits test normal, replace the inoperative front parking lamp.



Rear Park Lamps Malfunction
1. Ignition OFF, disconnect the harness connector at the inoperative rear tail lamp assembly.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the appropriate ground circuit terminal listed below and ground.

* Left rear tail lamp assembly ground circuit terminal 1 - 3 Door
* Left rear tail lamp assembly ground circuit terminal 6 - 5 Door
* Right rear tail lamp assembly ground circuit terminal 6 - 3 Door
* Right rear tail lamp assembly ground circuit terminal 1 - 5 Door


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

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

* Left rear park lamp control circuit terminal 5
* Right rear park lamp control circuit terminal 2

4. Command the Rear Outer Combination Lamps Test 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 REC.
• 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 REC.

5. If all circuits test normal, replace the inoperative tail lamp circuit board.



License Lamps Malfunction
1. Ignition OFF, disconnect the harness connector at the inoperative license lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Command the License Plate Light Test 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 REC.
• 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 REC.

5. If all circuits test normal, replace the inoperative license lamp.



Side Marker Lamps Malfunction
1. Ignition OFF, disconnect the harness connector at the inoperative side marker lamp.
2. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit terminal 1 and ground.

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

3. Connect a test lamp between the control circuit terminal 2 and ground.
4. Command the Rear Side Markers Test 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 REC.
• 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 REC.

5. If all circuits test normal, replace the inoperative side marker lamp.



Repair Instructions

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

* Headlamp Switch Replacement (Service and Repair)
* Rear License Lamp Replacement (Service and Repair)
* Headlamp Bulb Replacement (without High Intensity) (Service and Repair)
* Front Side Marker Lamp Replacement (Front Side Marker Lamp Replacement)
* Rear Side Marker Lamp Replacement (Rear Side Marker Lamp Replacement)
* Tail Lamp Circuit Board Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for IPC, REC, or UEC replacement, setup, and programming


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