Tail Light Bulb

This procedure covers removal and replacement of the tail light bulbs on a 2009 Aston Martin DB9, accessed from inside the trunk compartment.

Warnings

Tools required

Parts

• Tail light bulb × 1 — Use OEM specification for bulb type (typically W21W or P21W depending on position)

Preparation

1. Park vehicle on level surface and turn off ignition
2. Allow tail lights to cool if recently used
3. Open trunk and prop open with support rod if equipped
4. Identify which tail light bulb requires replacement (brake, turn signal, reverse, or tail light position)

Procedure

1. 1

   Locate tail light assembly access
   From inside the boot (trunk), access the rear of the tail light assembly on the side requiring bulb replacement. On the DB9 the tail lamp unit is retained by fasteners accessed through the boot trim; consult the vehicle-specific service documentation to confirm whether access is via a removable trim panel/access flap or by removing the lamp unit from the exterior. Note: From inside the boot (trunk), access the rear of the tail light assembly on the side requiring bulb replacement. On the DB9 the tail lamp unit is retained by fasteners accessed through the boot trim; consult the vehicle-specific service documentation to confirm whether access is via a removable trim panel/access flap or by removing the lamp unit from the exterior. Note: verify against OEM documentation whether the affected position uses a replaceable bulb or a non-serviceable LED module before proceeding. Note: verify against OEM documentation whether the affected position uses a replaceable bulb or a non-serviceable LED module before proceeding.
2. 2

   Remove trunk liner fasteners
   Identify and remove the fasteners securing the trim/access panel behind the tail light assembly. Confirm the exact fastener count, type (Torx screws versus plastic trim clips), and driver size against the DB9 service documentation before removal, as these are not confirmed in this procedure, and store any fasteners safely.
   ℹ️Some fasteners may be hidden under folded edges of the liner material; carefully inspect all edges before pulling on the panel.
3. 3

   Release trunk liner panel
   Carefully pull the trunk liner panel away from the body to expose the back of the tail light assembly. The panel may have plastic clips in addition to the Torx fasteners. Use trim panel removal tools to gently pry and release any clips without breaking them. Fold or position the liner out of the way to provide clear access to the tail light bulb holders.
4. 4

   Identify bulb holder
   Locate the specific bulb holder for the failed bulb on the back of the tail light assembly. The DB9 tail light assembly contains multiple lighting functions (brake/tail, turn signal, reverse, and position/marker). Verify against DB9 documentation which functions are replaceable bulbs versus non-serviceable LED modules before proceeding. Each has a separate bulb holder socket that twists or pulls out from the assembly.
5. 5

   Remove bulb holder
   Grasp the bulb holder firmly and rotate it counterclockwise approximately 1/4 turn (typically 45-90 degrees) until it releases from the tail light housing. Pull the holder straight out to extract it from the assembly. If the holder has a locking tab instead of a twist mechanism, press the tab and pull straight out.
6. 6

   Remove failed bulb
   Remove the failed bulb from the holder. Most bulbs are either bayonet-style (push and twist counterclockwise) or push-fit wedge-style (pull straight out). Inspect the bulb holder socket for any corrosion, discoloration, or damage. If corrosion is present, clean gently with electrical contact cleaner and a soft brush.
7. 7

   Install new bulb
   Using a clean cloth or gloves, install the new bulb into the holder. For bayonet-style bulbs, align the pins with the slots in the holder and push in while rotating clockwise until it locks. For wedge-style bulbs, push firmly straight into the socket until fully seated. Verify the bulb is secure in the holder.
8. 8

   Reinstall bulb holder
   Insert the bulb holder back into the tail light assembly housing, aligning any guide tabs or notches. Rotate clockwise approximately 1/4 turn until it locks into place, or press until the locking tab engages. Gently tug on the holder to confirm it is secured.
9. 9

   Test bulb operation
   Before reinstalling the trunk liner, turn the ignition to the ON position (or have an assistant operate the controls) and test the new bulb function. Test brake lights with the brake pedal, turn signals with the turn signal stalk, and tail lights by turning on the headlights. Note: the DB9 monitors bulb circuits via CANbus, so an incorrect-wattage or non-OEM LED bulb may trigger a bulb-failure warning even if it illuminates — use the correct OEM-specified bulb. To test reverse lights, ensure the vehicle is secured with the parking brake set and wheels chocked before selecting reverse. Verify proper operation before proceeding.
10. 10

    Reinstall trunk liner panel
    Position the trunk liner panel back into place, ensuring any clips align with their body mounting points. Press firmly along the panel edges to engage the clips. Reinstall all Torx fasteners in their original locations and tighten snugly, but do not overtighten as this can crack the trim panel mounting points.

Reassembly

1. Ensure all trunk liner fasteners are installed and tightened
2. Verify trunk liner panel sits flush and does not rattle
3. Close trunk and verify proper latching

Verification

• Perform a complete lighting system check: turn on headlights to verify tail lights, press brake pedal to verify brake lights, activate turn signals left and right, and shift to reverse to verify reverse lights
• Walk around the vehicle to visually confirm the replaced bulb is functioning at the correct brightness and matches the opposite side
• Ensure no warning messages appear on the instrument cluster regarding lighting system faults

Related trouble codes on this vehicle

Codes that commonly send this job to the bay — tap one for symptoms, causes, and diagnostic steps.

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