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Park Lamps Malfunction




Park 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 LAMP fuse in the instrument panel (I/P) fuse block supplies battery voltage to both the coil and switch sides of the PRK LAMP relay, also located in the I/P fuse block. When the headlamp switch is placed in either the PARK or HEAD position, ground is supplied to the body control module (BCM) on the park lamp switch ON signal circuit. The BCM reacts to the park lamp switch ON signal by applying ground to the park lamp relay control circuit. This energizes the park lamp relay coil, causing the relay switch contacts to close applying voltage to all park, tail, marker, and license lamps.

Reference Information
Schematic Reference

Exterior Lights Schematics Exterior Lights Schematics
Connector End View Reference

Component Connector End Views
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

Ignition ON, observe the scan tool Park Lamp Switch 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.

Circuit/System Testing

Park Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition OFF, verify that a test lamp illuminates between B+ and the ground circuit terminal 4.

• 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 OFF.

• If not the specified value, test the signal circuit terminal 6 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 6 and ground. Verify the scan tool Park Lamp Switch 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 BCM.

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

Park, License, and/or Tail Lamps Malfunction
1. Ignition OFF, disconnect the park lamp relay.
2. Ignition ON, verify a test lamp does not illuminate between the control circuit terminal 87 and ground.

• If the test lamp illuminates, test the control circuit for a short to voltage.

3. Verify a test lamp illuminates between the B+ circuit terminal 30 and ground.

• If the test lamp does not illuminate, test the B+ circuit for a short to ground or an open/high resistance. If the circuit tests normal and the B+ circuit fuse is open, test the control circuit terminal 87 for a short to ground. If the circuit tests normal, replace the park lamp relay.

4. Verify a test lamp illuminates between the B+ circuit terminal 85 and ground.

• If the test lamp does not illuminate, test the B+ circuit for an open/high resistance.

5. Disconnect the harness connector at the inoperative park/license/marker lamp.
6. Ignition OFF, exterior lamps OFF, test for less than 5.0 ohms between the ground circuit and ground.

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

7. Connect the harness connector at the inoperative park/license/marker lamp.
8. Connect a 10A fused jumper wire between the B+ circuit terminal 30 and the control circuit terminal 87. Verify the park/marker lamps are activated.

• If the park/marker lamps do not activate, test the control circuit for an open/high resistance. If the circuit tests normal, replace the inoperative park/license/marker lamp.

9. Connect a test lamp between the B+ circuit terminal 85 and the control circuit terminal 86.
10. Command the 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 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.

11. If all circuits test normal, test or replace the park lamp relay.

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
* Tail Lamp Replacement Service and Repair
* Park/Turn Signal Lamp Bulb Replacement Service and Repair
* Relay Replacement (Attached to Wire Harness) Relay Replacement (Attached to Wire Harness)Relay Replacement (Within an Electrical Center) Relay Replacement (Within an Electrical Center)
* Control Module References Control Module References for BCM replacement, setup, and programming

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