GM Service Manual Online
For 1990-2009 cars only

Headlamp Leveling Control Module Replacement LWB

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.

    Caution: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

       • Never open the high intensity discharge system ballast or the arc tube assembly starter.
       • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

    Caution: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.

  1. Disconnect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Remove the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement.
  3. Remove the headlamp assembly. Refer to Headlamp Replacement.

  4. Object Number: 1946987  Size: SH
  5. Disconnect the headlamp levelling module electrical connector (2).
  6. Remove the headlamp levelling module retaining torx screws (1).
  7. Remove the headlamp levelling module.

Installation Procedure


    Object Number: 1946987  Size: SH
  1. Install the headlamp levelling module.
  2. Connect the headlamp levelling module electrical connector (2).
  3. Notice: Refer to Fastener Notice in the Preface section.

  4. Install the headlamp levelling module retaining torx screws (1).
  5. Tighten
    Tighten the screws to 4.0 N·m (35 lb in).

  6. Install the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement.
  7. Connect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  8. Check all vehicle lights for correct operation.

Headlamp Leveling Control Module Replacement SWB

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.

    Caution: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

       • Never open the high intensity discharge system ballast or the arc tube assembly starter.
       • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

    Caution: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.

  1. Disconnect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Caution: Refer to Safety Glasses Caution in the Preface section.

    Caution: Refer to Vehicle Lifting Caution in the Preface section.

  3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.

  4. Object Number: 1946996  Size: SH

    Important: The headlamp levelling linkages are not a serviceable item and should be replaced as a complete assembly.

  5. Remove the headlamp levelling sensor linkage retaining bolt (1).

  6. Object Number: 1946994  Size: SH
  7. Disconnect the headlamp levelling sensor electrical connector (1).

  8. Object Number: 1946999  Size: SH
  9. Remove the head lamp levelling sensor retaining bolts.
  10. Remove the head lamp levelling sensor.

Installation Procedure


    Object Number: 1946999  Size: SH
  1. Install the head lamp levelling sensor.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the head lamp levelling sensor retaining bolts.
  4. Tighten
    Tighten the bolts to 9.0 N·m (80 lb in).


    Object Number: 1946994  Size: SH
  5. Connect the headlamp levelling sensor electrical connector (1).

  6. Object Number: 1946996  Size: SH
  7. Install the head lamp levelling sensor linkage.
  8. Notice: Refer to Fastener Notice in the Preface section.

  9. Install the head lamp levelling sensor linkage retaining nut (1).
  10. Tighten
    Tighten the nut to 4.0 N·m (35 lb in).

  11. Lower the vehicle. Refer to Lifting and Jacking the Vehicle.
  12. Connect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  13. Check all vehicle lights for correct operation.

Headlamp Leveling Control Module Replacement Front

Removal Procedure

    Caution: Refer to Battery Disconnect Caution in the Preface section.

    Caution: The high intensity discharge system produces high voltage and current. To reduce the risk of severe shocks and burns:

       • Never open the high intensity discharge system ballast or the arc tube assembly starter.
       • Never probe between the high intensity discharge system ballast output connector and the arc tube assembly.

    Caution: The high intensity discharge system produces high voltage and current. In order to reduce the risk of severe shocks and burns, the battery negative cable must be disconnected any time service work is being performed on or around the high intensity discharge system.

  1. Disconnect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  2. Caution: Refer to Safety Glasses Caution in the Preface section.

    Caution: Refer to Vehicle Lifting Caution in the Preface section.

  3. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle.
  4. Remove the air deflector. Refer to Front Air Deflector Replacement.

  5. Object Number: 1946990  Size: SH
  6. Using a suitable tool, remove the headlamp levelling sensor linkage (1) from the front suspension sway bar linkage.

  7. Object Number: 1946992  Size: SH
  8. Disconnect the headlamp levelling sensor electrical connector (3).
  9. Remove the headlamp levelling sensor retaining bolts (1).
  10. Remove the headlamp levelling sensor (2).

Installation Procedure


    Object Number: 1946992  Size: SH
  1. Install the headlamp levelling sensor (2).
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the headlamp levelling sensor retaining bolts (1).
  4. Tighten
    Tighten the bolts to 8.0 N·m (71 lb in).

  5. Connect the headlamp levelling sensor electrical connector (3).
  6. Install the headlamp levelling sensor linkage to the sway bar linkage, listen for an audible click to confirm fitting.
  7. Install the air deflector. Refer to Front Air Deflector Replacement.
  8. Lower the vehicle. Refer to Lifting and Jacking the Vehicle.
  9. Connect the battery ground cable. Refer to Battery Negative Cable Disconnection and Connection.
  10. Check all vehicle lights for correct operation.