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
Battery voltage is applied at all times to both the coil and switch sides of the PRK LAMP relay located in the underhood fuse block. The turn signal/multifunction switch is suppled with ground at G201 at all times. When the headlamp switch is placed in either the HEAD or PARK position, ground is applied to the park lamp signal circuit to the body control module (BCM). The BCM responds by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil causing the relay switch contacts to close allowing battery voltage to flow to all of the park, tail, license, and marker 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
Ignition ON, observe the scan tool Park Lamp Switch parameter while cycling the park lamp switch ON and OFF. The parameters should change between Active and Inactive.
If the parameters do not change between the commanded states, refer to Park Lamp Switch Malfunction.
If the parameters change between the commanded states, refer to Park, License, and/or Tail Lamps Malfunction.
Circuit/System Testing
Park Lamp Switch Malfunction
1. Ignition OFF, disconnect the X1 harness connector at the turn signal/multifunction switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 1.
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Park Lamp Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 3 for a short to ground. If the circuit tests normal, replace the BCM.
4. Install a 3A fused jumper wire between the signal circuit terminal 3 and ground. Verify the scan tool Park Lamp Switch parameter is Active.
• 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 BCM.
5. If all circuits test normal, test or replace the turn signal/multifunction switch.
Park, License, and/or Tail Lamps Malfunction
1. Ignition OFF, disconnect the X2 harness connector at the underhood fuse block.
2. Connect a test lamp between the control circuit terminal B7 and B+.
3. Command the Parking 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 ground. If the circuit tests normal, replace the 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 BCM.
4. Ignition OFF, connect the X2 harness connector at the underhood fuse block.
5. Disconnect the harness connector at the inoperative park/license/marker lamp.
6. Ignition OFF, exterior lamps OFF, test for less than 5 ohms between the appropriate ground circuit terminal listed below and ground.
* License lamps ground terminal B
* Tail/stop and turn signal lamps ground terminal C
* Marker lamps ground terminal B
* Front park/turn signal lamps ground terminal G
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Connect a test lamp between the appropriate control circuit terminal listed below and ground.
* License lamps control terminal A
* Tail/stop and turn signal lamps control terminal B
* Marker lamps control terminal A
* Front park/turn signal lamps control terminal B
8. Command the Parking 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 underhood fuse block.
• If the test lamp is always OFF and the circuit fuse is good, test the control circuit for an open/high resistance. If the circuit tests normal, replace the underhood fuse block.
• If the test lamp is always OFF and the circuit fuse is open, test the control circuit for a short to ground. If the circuit tests normal, replace the underhood fuse block.
9. If all circuits test normal, test or replace the inoperative park/license/marker lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Tail Lamp Replacement (Chevrolet Coupe) (Tail Lamp Replacement (Chevrolet Coupe))Tail Lamp Replacement (Chevrolet, Pontiac Sedan) (Tail Lamp Replacement (Chevrolet, Pontiac Sedan))Tail Lamp Replacement (Chevrolet European) (Tail Lamp Replacement (Chevrolet European))
* Rear License Plate Lamp Replacement (Chevrolet) (Service and Repair)Rear License Plate Lamp Replacement (Pontiac G5) (Service and Repair)
* Rear License Plate Lamp Bulb Replacement (Chevrolet) (Service and Repair)Rear License Plate Lamp Bulb Replacement (Pontiac G5) (Service and Repair)
* Turn Signal Multifunction Switch Replacement (Turn Signal Multifunction Switch Replacement)
* Front Side Marker Lamp Bulb Replacement (Front Side Marker Lamp Bulb Replacement)
* Rear Side Marker Lamp Bulb Replacement (Pontiac G5 Coupe) (Rear Side Marker Lamp Bulb Replacement)Rear Side Marker Lamp Bulb Replacement (Chevrolet Sedan) (Rear Side Marker Lamp Bulb Replacement)
* Control Module References (Programming and Relearning)for BCM replacement, setup, and programming