Headlamp Leveling Malfunction
Headlamp Leveling 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
Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlight switch. The headlight switch is a resistance ladder switch and wired to each headlamp leveling motor. With the ignition in ON position the headlight switch and each headlamp leveling motor is applied to B+. Each headlamp leveling motor is permanently grounded.
Reference Information
Schematic Reference
Headlights/Daytime Running Lights (DRL) Schematics (Headlights/Daytime Running Lights (DRL) Schematics)
Connector End View Reference
Component Connector End Views (Connector End Views By Name)
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 (Programming and Relearning) for scan tool information
Circuit/System Verification
Ignition ON, cycle the headlamp leveling switch in each position while observing both headlamps. Both headlamps should operate to the appropriate position when commanded.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the appropriate headlamp assembly.
2. Ignition OFF, test for less than 5 ohm between the ground circuit terminal 3 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, connect a test lamp between the ignition circuit terminal 1 and ground. The test lamp should illuminate.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
4. Ignition OFF, disconnect the harness connector at the S30 Headlamp Switch.
5. Ignition ON, connect a test lamp between the ignition circuit terminal 9 and ground. The test lamp should illuminate.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
6. Ignition ON, test for less than 0.3 V between the signal circuit terminal 10 and ground.
• If greater than the specified range, test the signal circuit for a short to voltage.
7. Ignition OFF, test for greater than 500 kohm between the signal circuit terminal 10 and ground.
• If less than the specified range, test the signal circuit for a short to ground.
8. Ignition OFF, test for less than 5 ohm between the signal circuit terminal 10 at the S30 Headlamp Switch and the control circuit terminal 2 at the appropriate headlamp assembly.
• If greater than the specified range, test the signal circuit for an open/high resistance.
9. Ignition OFF, reconnect the harness connector at the S30 Headlamp Switch. Connect a test lamp between the control circuit terminal 2 at the appropriate headlamp assembly and ground.
10. Switch the headlamp leveling switch in each position. The test lamp illumination should change in each position.
• If the test lamp does not illuminate or does not change their illumination, replace the S30 Headlamp Switch.
11. If all circuits test normal, replace the appropriate headlamp assembly.
Repair Instructions
Perform the Diagnostic Repair Verification (Verification Tests) after completing the diagnostic procedure.
* Headlamp Switch Replacement (Service and Repair)
* Headlamp Replacement (Service and Repair)