Headlamp Leveling Malfunction
Headlamp Leveling 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
With the ignition in the ignition ON or ignition RUN position, voltage is supplied through the IGN E fuse. It then is dispersed to the headlamp switch and the left and right headlamp leveling actuators. The headlamp leveling actuators are then controlled by the headlamp switch to reach the desired position. The headlamp switch is permanently grounded at G201. The left headlamp leveling actuator is permanently grounded at G107 and the right headlamp leveling actuator is permanently grounded at G103.
Reference Information
Schematic Reference
Headlight Leveling Schematics (Headlight Leveling 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 Testing
Headlamp Leveling Actuator Malfunction
1. Ignition OFF, disconnect the harness connectors at the headlamp switch.
2. Test for less than 5.0 ohms between the ground circuit terminal C X1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
3. Ignition ON, verify that a test lamp illuminates between the headlamp switch ignition circuit terminal G X2 and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
4. Reconnect the harness connectors at the headlamp switch.
5. Disconnect the harness connector at the inoperative headlamp leveling actuator.
6. Test for less than 5.0 ohms between the ground circuit terminal 1 and ground.
• If greater than the specified range, test the ground circuit for an open/high resistance.
7. Ignition ON, verify that a test lamp illuminates between the headlamp leveling actuator ignition circuit terminal 3 and ground.
• If the test lamp does not illuminate, test the ignition circuit for a short to ground or an open/high resistance.
8. Ignition ON, test for 2.0 - 8.0 volts between the headlamp leveling actuator signal circuit terminal 2 and ground while operating the leveling switch from the lowest to highest setting.
• If less than the specified range, test the signal circuit for a short to ground or an open/high resistance. If the circuit tests normal, replace the headlamp switch.
• If greater than the specified range, test the signal circuit for a short to voltage. if the circuit tests normal, replace the headlamp switch.
9. If all circuits test normal, test or replace the inoperative headlamp leveling actuator.
Repair Instructions
Perform the after completing the diagnostic procedure.
* Headlamp Aiming (Adjustments)
* Headlamp Switch Replacement (Service and Repair)
* Headlamp Replacement (Envoy) (Service and Repair)Headlamp Replacement (TrailBlazer) (Service and Repair)