Headlamp Leveling Malfunction (V-Series)
Headlamp Leveling Malfunction (V-Series)
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
Each headlamp assembly contains a headlamp leveling motor that is controlled by the headlamp control module. The front and rear suspension position sensors provide the electronic suspension control (ESC) module with suspension position information. Each sensor receives a 5-volt reference, signal, and low reference circuits from the ESC. The sensors are connected to the control arms of the front and rear suspension. As the vehicle travels, the suspension compresses and rebounds moving the suspension position sensor arms. This causes the signal output of the sensor to change. The ESC sends the suspension position sensor values to the headlamp control module via serial data. The headlamp control module compares the information from both suspension position sensors and adjusts the headlamp leveling as needed. The headlamp control module is wired to each headlamp leveling motor with 4 directional motor control circuits.
Reference Information
Schematic Reference
Headlight Leveling Schematics (Headlight Leveling Schematics)
Electronic Suspension Control Schematics (Electrical Diagrams)
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
Ignition ON, with a scan tool, command the DHL Motor Control Up and Down while observing both headlamps. Both headlamps should operate to the Up and Down positions when commanded.
Circuit/System Testing
1. Ignition OFF, disconnect the harness connector at the inoperative headlamp.
2. Remove the AFS 15A fuse.
3. Ignition OFF, scan tool OFF, test for 10 ohms -25K ohms between each control circuit terminal listed below and ground.
* Headlamp leveling motor control terminal 1
* Headlamp leveling motor control terminal 2
* Headlamp leveling motor control terminal 3
* Headlamp leveling motor control terminal 4
• If greater than the specified range, test the control circuit for a short to voltage or an open/high resistance. If the circuit tests normal, replace the headlamp control module.
• If less than the specified range, test the control circuit for a short to ground. If the circuit tests normal, replace the headlamp control module.
4. Install the AFS 15A fuse.
5. Ignition ON, scan tool OFF, headlamps ON, verify that a test lamp does not illuminate between each control circuit terminal listed below and ground.
* Headlamp leveling motor control terminal 1
* Headlamp leveling motor control terminal 2
* Headlamp leveling motor control terminal 3
* Headlamp leveling motor control terminal 4
• If the test lamp illuminates, test the control circuit for a short to voltage. If the circuit tests normal, replace the headlamp control module.
6. 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 Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT6) (Service and Repair)Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT7) (Service and Repair)Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (TT8) (Service and Repair)Headlamp Assembly or Headlamp Bulb and/or Cornering, Sidemarker, Park, Turn Signal Bulb Replacement (Minus TT6/TT7/TT8/T84/T85) (Service and Repair)
* Control Module References (Programming and Relearning) for headlamp control module replacement, setup, and programming