Dimmer Switch

Replacement of the dimmer (headlight intensity) switch located in the driver's side lower dash panel, requiring removal of lower trim panels and switch module disconnection.

Warnings

Tools required

Parts

• Dimmer switch assembly × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key fob from vehicle interior
3. Disconnect battery negative terminal and wait 2 minutes for airbag system capacitor discharge
4. Set driver's seat to rearmost position for working access
5. Ensure steering wheel is in straight-ahead position

Procedure

1. 1

   Remove Driver's Side Lower Dash Panel
   Locate the lower dash panel beneath the steering column (verify against the vehicle whether this panel also covers fuse box access). Identify Torx fasteners securing the panel. Remove the Torx fasteners (verify exact count and size against the 2009 DB9 before proceeding; commonly T20/T25 on this platform). Gently pull the lower edge of the panel outward to release the retention clips at the top edge. Support the panel and disconnect any electrical connectors for courtesy lighting if present. Remove the panel completely and set aside. Note: Verify instrument panel illumination intensity changes smoothly from minimum to maximum brightness settings Note: Verify instrument panel/dashboard illumination brightness changes smoothly from minimum to maximum dim settings Note: Test instrument panel and interior illumination at both day and night settings (parking lights/headlights on) to ensure the dimmer rheostat adjusts panel brightness correctly. Note: With the parking/running lights on, cycle the dimmer through its full range and confirm dashboard illumination responds across all positions. Note: Disconnect battery negative terminal and wait at least 10 minutes (or per Aston Martin specification) before working near airbag system components to allow SRS capacitor discharge and prevent accidental deployment.
2. 2

   Access Dimmer Switch Module
   With the lower panel removed, locate the dimmer switch assembly. On the 2009 DB9 the exact mounting location must be confirmed against Aston Martin service documentation, as it may be integrated into the center console/fascia control cluster rather than the steering column shroud. Identify the mounting fasteners securing the switch module housing (usually 2 Torx screws, T20 size). Note: The switch may be integrated into a multi-function control module or located within the dashboard switch panel; verify exact location against 2009 DB9 interior layout documentation before proceeding. Note: The switch may be integrated into a multi-function control module; verify its exact location on the 2009 DB9. Identify the mounting fasteners securing the switch module housing (confirm count and Torx size against the vehicle).
3. 3

   Disconnect Dimmer Switch Wiring
   Locate the electrical connector on the rear of the dimmer switch module. Press the locking tab on the connector and pull straight back to disconnect. If the connector has a secondary lock (sliding safety clip), slide it to the unlock position before pressing the primary locking tab. Note the connector orientation for reinstallation.
4. 4

   Remove Dimmer Switch Mounting Fasteners
   Remove the Torx mounting fasteners securing the dimmer switch assembly (confirm exact count and Torx size against 2009 DB9 service documentation before proceeding). Keep fasteners organized for reinstallation. Keep fasteners organized for reinstallation. If the switch is part of a larger multi-function module, you may need to release additional clips or fasteners specific to the switch section.
5. 5

   Extract Dimmer Switch Assembly
   Carefully pull the dimmer switch assembly straight out from its mounting position. Be aware of any additional guide pins or alignment tabs that may require slight angling during removal. Inspect the mounting bracket and surrounding area for any damage or wear.
6. 6

   Prepare New Dimmer Switch
   Remove the new dimmer switch from packaging and compare it with the old unit to verify correct replacement part. Check that all mounting tabs and connector pins are intact and undamaged. If the switch includes any adjustment or calibration settings, ensure they match the original configuration.
7. 7

   Install New Dimmer Switch
   Position the new dimmer switch assembly into the mounting bracket, aligning any guide pins or tabs. Ensure the switch is fully seated in its mounting position before fastening. Install the 2 Torx mounting fasteners and tighten evenly to secure the switch. Do not overtighten plastic mounting points.
8. 8

   Reconnect Electrical Connector
   Align the electrical connector with the switch terminals and push firmly until the locking tab clicks into place. If equipped with a secondary lock, slide it to the locked position after the main connector is seated. Gently tug on the connector to verify secure connection.
9. 9

   Reinstall Lower Dash Panel
   If applicable, reconnect any courtesy light connectors to the lower dash panel. Position the panel into place, engaging the upper retention clips first. Press the lower edge firmly to seat all clips. Install all Torx fasteners and tighten securely (hand-tight with Torx driver, do not overtorque plastic mounting points).

Reassembly

1. Reconnect battery negative terminal
2. Return driver's seat to normal operating position
3. Verify all trim panels are securely fastened with no gaps or rattles

Verification

• Turn ignition to ON position (engine off) and test dimmer switch through full range of adjustment
• Verify headlight intensity changes smoothly from minimum to maximum dim settings
• Confirm instrument panel illumination responds correctly to dimmer switch input
• Check that all other dashboard functions (turn signals, wipers, etc.) operate normally
• Test with headlights in both low beam and high beam modes to ensure dimmer function works in all lighting configurations
• Inspect lower dash panel for proper fit and secure mounting

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