Headlight Switch

This procedure removes and replaces the headlight switch assembly in the driver's side dashboard control panel of the 2019 Mercedes-Benz G-Class.

Warnings

Tools required

Parts

• Headlight switch assembly × 1 — A4639050800 or A4639051000 depending on equipment

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key
3. Disconnect battery negative terminal using 10mm socket and wait 3 minutes
4. Ensure steering wheel is in straight-ahead position for access to lower dash area

Procedure

1. 1

   Access Lower Dash Panel
   Open the driver's door fully. Locate the lower dashboard trim panel below the steering column. This panel covers the area from the footwell to the lower edge of the instrument cluster.
2. 2

   Remove Lower Dash Trim Panel
   Using a plastic trim tool, carefully release the lower dash panel clips starting from the bottom edge. There are typically 4-6 clips securing this panel. Pull the panel away gently, working from bottom to top. Set the panel aside.
3. 3

   Remove Driver's Side Control Panel Trim
   Locate the control panel trim surround on the left side of the steering column that houses the rotary headlight switch and adjacent light-related controls. This trim piece is secured by clips around its perimeter. Insert a plastic trim tool at the bottom edge and carefully work around the perimeter to release the retaining clips. There should be 6-8 clips total holding this panel.
4. 4

   Access Headlight Switch Fasteners
   With the control panel trim pulled forward approximately 2-3 inches, you will have access to the rear of the switch assembly. Identify the Torx fasteners securing the headlight switch module to the back of the trim panel. There are 2 Torx screws (likely T20 or T25) holding the switch assembly in place.
5. 5

   Disconnect Electrical Connector
   Locate the electrical connector on the back of the headlight switch assembly. Press the locking tab on the connector and pull it straight back to disconnect it from the switch. Note the connector orientation for reinstallation.
6. 6

   Remove Switch Fasteners
   Remove the 2 Torx screws securing the headlight switch to the control panel trim. Keep these fasteners in a safe location as they will be reused.
7. 7

   Remove Headlight Switch
   With the fasteners removed and connector disconnected, carefully pull the headlight switch assembly rearward out of the control panel trim. The switch should come free from the trim panel. Inspect the mounting points on the trim panel for any damage.
8. 8

   Install New Headlight Switch
   Position the new headlight switch assembly into the control panel trim, aligning the mounting holes with the fastener locations. Ensure the switch is fully seated and flush with the front surface of the trim panel.
9. 9

   Secure Switch Assembly
   Install the 2 Torx screws through the back of the trim panel into the headlight switch assembly. Tighten the screws evenly to ensure the switch sits flush. Do not overtighten as the trim panel is plastic.
10. 10

    Reconnect Electrical Connector
    Push the electrical connector firmly onto the back of the headlight switch until you hear and feel the locking tab click into place. Gently tug on the connector to verify it is fully seated.
11. 11

    Reinstall Control Panel Trim
    Position the control panel trim assembly back into the dashboard opening. Align all clips with their receptacles in the dashboard structure. Press firmly around the perimeter until all clips snap into place. Verify the panel is flush and secure.
12. 12

    Reinstall Lower Dash Panel
    Position the lower dash panel into place below the steering column. Align the clips with their receptacles and press firmly until all clips engage. Ensure the panel is properly seated and flush with surrounding trim.
13. 13

    Reconnect Battery and Test
    Reconnect the battery negative terminal. Start the vehicle and test all headlight switch functions: low beams, auto mode, parking lights, and any fog light controls (note high beams are controlled by the turn/multifunction stalk, not the rotary switch). Verify the instrument cluster does not show any warning lights related to the lighting system.

Reassembly

1. Reinstallation follows removal in reverse order
2. Ensure all electrical connectors are fully seated and locked before reassembling trim panels
3. Press trim panels firmly to engage all retaining clips
4. If the new switch is a replacement unit (not original Mercedes part), coding may be required using Mercedes XENTRY diagnostic system

Verification

• Test all headlight switch positions: off, parking lights, low beams, high beams, and auto mode if equipped
• Verify fog lights operate if vehicle is equipped
• Check that instrument cluster lighting controls function properly
• Confirm no warning lights appear on instrument cluster
• Verify all dashboard trim panels are secure and flush with no gaps or rattles

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