Roof Clearance Lamps Malfunction
Roof Clearance 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 roof marker lamps are a dealer installed option and operate whenever the park lamps are on. When the park lamps or headlamps are turned to the ON position at the headlight switch, voltage is supplied to the roof marker lamps through the park lamp control circuit. The roof marker lamps are grounded at all times at G105.
Diagnostic Aids
Verify that the park lamps are operating correctly prior to diagnosing a roof marker lamp condition.
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 Park Lamp Signal parameter while turning the park lamps ON and OFF. The reading should change between Inactive and Active.
• If not the specified value, refer to the Park Lamp Switch Circuit Test.
2. Ignition ON, command the park lamps ON and OFF with a scan tool. The roof marker lamps should turn On and Off.
• If the roof marker lamps do not turn On and Off, refer to the Roof Marker Lamp Malfunction Test.
Circuit/System Testing
Park Lamp Switch Malfunction
1. Ignition OFF, disconnect the harness connector at the headlamp switch.
2. Ignition ON, verify the scan tool Park Lamp Signal 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 BCM.
3. Install a 3A fused jumper wire between the signal circuit terminal 2 and ground. Verify the scan tool Park Lamp Signal parameter is Active.
• If not the specified value, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the BCM.
4. If all circuits test normal, test or replace the headlamp switch.
Roof Marker Lamp Malfunction
1. Ignition OFF, disconnect the harness connector at the inoperative roof marker lamp.
2. Exterior lamps OFF, test for less than 5 ohms between the ground circuit terminal B and ground.
• If greater than the specified range, test the ground circuit for and open/high resistance.
3. Connect a test lamp between the control circuit terminal A and the ground circuit terminal B.
4. Ignition ON, 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 voltage.
• If the test lamp is always off, test the control circuit for a short to ground or an open/high resistance.
5. If all circuits test normal, replace the inoperative roof marker lamp.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Headlamp Switch Replacement (Service and Repair)
* Roof Identification Lamp Bulb Replacement (Roof Identification Lamp Bulb Replacement)
* Control Module References (Programming and Relearning) for BCM replacement, programming, and setup