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, tail and marker lamps, including the license lamps, are turned ON when the headlamp switch is placed in the PARK or HEAD position or anytime the headlights are requested. The underhood fuse block supplies battery positive voltage to both the park lamp relay switch contacts and the park lamp coil circuit. The BCM provides a ground or control circuit to the park lamp relay coil circuit. When the park lamps are turned ON, the BCM energizes the park lamp relay. If the headlight switch is left in the ON position, the inadvertent power control feature will turn OFF the park, tail and marker lamps approximately 10 minutes after the ignition switch is turned to the OFF position. If the driver places the headlight switch in the ON position after the ignition switch has been turned OFF, or if the ignition switch is in the ACCY position, the park, tail and marker lamps will remain ON until turned OFF or the battery runs dead.
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 Parklamp Switch parameter while cycling the headlamp switch between the PARK and OFF positions. The parameter should cycle between Active and Inactive.
• If the parameter does not cycle between the specified values, refer to Park Lamp Switch Malfunction.
2. Ignition ON, command the Parking Lamps ON and OFF with a scan tool. The Parking Lamps should turn ON and OFF.
• If the lamps do not change between the commanded states, refer to the Park Lamp Malfunction.
Circuit/System Testing
Park Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp and panel dimmer switch.
2. Ignition OFF, test for less than 5.0 ohms between the ground circuit terminal 8 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify the scan tool Parklamp Switch parameter is Inactive.
• If not the specified value, test the signal circuit terminal 2 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 2 and ground circuit terminal 8. Verify the scan tool Parklamp Switch parameter is Active.
• If not the specified value, test the signal circuit for a short to voltage or open/high resistance. If the circuit tests normal, replace the BCM.
5. If all circuits test normal, test or replace the headlamp and panel dimmer switch.
Park Lamp Malfunction
1. Ignition OFF, disconnect the park lamp relay.
2. Connect a test lamp between the B+ circuit terminal 30 and ground. The test should illuminate.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance
3. Connect a test lamp between the B+ circuit terminal 85 and ground. The test should illuminate.
• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance
4. Connect a test lamp between the relay control circuit terminal 86 and the B+ circuit terminal 85.
5. 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 relay control circuit for a short to ground. If the circuit tests normal, replace the BCM.
• If the test lamp is always OFF, test the relay control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the BCM.
6. If all circuits test normal, test or replace the PRK LAMP relay.
7. Ignition OFF, reconnect the PRK LAMP relay.
8. Ignition OFF, disconnect the harness connector at the inoperative park lamp.
9. Verify that a test lamp illuminates when connected between B+ and the listed ground circuit terminal.
* Front Park/Turn Signal lamp terminal 1
* License lamp terminal B
* Marker Lamp terminal B
* Rear Tail/Stop Lamp terminal B
* Rear Tail/Stop and Turn Signal Lamp terminal A
* Roof Marker Lamp terminal B
* Roof Clearance Lamp terminal B
• If the test lamp does not illuminate, test the ground circuit for an open/high resistance.
10. Ignition ON, connect a test lamp between the listed control circuit terminal and ground.
* Front Park/Turn Signal lamp terminal 2
* License lamp terminal A
* Marker Lamp terminal A
* Rear Tail/Stop Lamp terminal A
* Rear Tail/Stop and Turn Signal Lamp terminal B
* Roof Marker Lamp terminal A
* Roof Clearance Lamp terminal A
11. 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.
12. If all circuits test normal, test or replace the inoperative lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Parking and Turn Signal Lamp Replacement (SUT Rear) (Parking and Turn Signal Lamp Replacement (SUT Rear))Parking and Turn Signal Lamp Replacement (SUV) (Parking and Turn Signal Lamp Replacement (SUV))
* Rear License Lamp Replacement (SUT) (Service and Repair)
* Tail/Turn Signal Lamp Replacement (SUV) (Tail/Turn Signal Lamp Replacement (SUV))Tail/Turn Signal Lamp Replacement (SUT) (Tail/Turn Signal Lamp Replacement (SUT))
* Headlamp Switch Replacement (Service and Repair)
* Control Module References (Programming and Relearning) for BCM replacement, programming, and setup.