Brake Light Switch

Replace the brake light switch located on the brake pedal assembly to restore brake light operation and cruise control functionality.

Warnings

Tools required

Parts

• Brake light switch × 1 — Use OEM Aston Martin specification

Preparation

1. Park vehicle on level ground and apply parking brake firmly
2. Turn ignition to OFF position and remove key from ignition
3. Open driver's door and leave it open for access throughout the procedure
4. Allow adequate time for any interior components to cool if vehicle was recently driven
5. Position work light to illuminate the area behind the brake pedal assembly

Procedure

1. 1

   Access the brake pedal area
   Adjust the driver's seat fully rearward to maximize working space. Lie on your back with your head near the driver's seat, positioning yourself to look upward behind the brake pedal assembly. Use the flashlight to locate the brake light switch, which is mounted on a bracket above the brake pedal arm. The switch will have an electrical connector attached and will be positioned where the brake pedal arm contacts it when the pedal is released.
2. 2

   Disconnect the electrical connector
   Locate the electrical connector on the brake light switch body. Identify the locking tab on the connector (typically a small tab or slide mechanism). Press or depress the locking tab while gently pulling the connector straight away from the switch. If the connector is difficult to access, use needle-nose pliers to carefully press the locking tab. Do not pull on the wiring harness itself, only on the connector body.
3. 3

   Remove the brake light switch
   Examine how the switch is mounted to the bracket. On the DB9, confirm the exact switch retention method against Aston Martin service documentation before proceeding, as it may use a twist-lock (quarter-turn/bayonet) mounting or a clip-retained system. If twist-lock: rotate the switch body in the release direction until it disengages from the mounting bracket, then pull it straight out. If clip-retained: locate the retaining clips on the switch body, compress them inward using your fingers or a small flat-blade screwdriver, then pull the switch straight out from the bracket. Note the orientation and position of the switch for installation reference.dy, compress them inward using your fingers or a small flat-blade screwdriver, then pull the switch straight out from the bracket. small flat-blade screwdriver, then pull the switch straight out from the bracket. Note the orientation and position of the switch for installation reference. Note: The exact mounting method for the DB9 brake light switch must be confirmed against OEM documentation before removal — do not force the switch. Common designs are either a bayonet/twist-lock (rotate the switch body to release, then withdraw straight out) or a clip-retained type (compress the retaining clips with your fingers or a small flat-blade screwdriver, then pull the switch straight out). Identify the actual retention type visually before applying any rotation or force to avoid damaging the switch or bracket. Note: The exact mounting method for the 2009 DB9 brake light switch must be verified against Aston Martin service documentation before removal. These switches are commonly retained by either a quarter-turn twist-lock or a snap-in clip. If twist-lock: rotate the switch body in the release direction (verify the exact direction against Aston Martin service documentation) until it releases from the mounting bracket, then pull it straight out. If clip-retained: locate the retaining clips on the switch body, compress them inward using your fingers or a small flat-blade screwdriver, then pull the switch straight out from the bracket.
4. 4

   Inspect the mounting bracket and pedal contact point
   With the old switch removed, inspect the mounting bracket for any cracks, damage, or wear. Check the brake pedal arm contact surface where it engages the switch plunger for any debris, wear, or damage. Clean the contact area and bracket with a clean cloth if necessary. Verify that the pedal return spring is functioning properly and the pedal returns fully to its rest position without binding.
5. 5

   Install the new brake light switch
   Take the new brake light switch and orient it to match the position of the removed switch. Insert the switch into the mounting bracket, ensuring the plunger or contact element is positioned to engage with the brake pedal arm properly. If twist-lock: insert the switch straight into the bracket, then rotate it in the lock direction (typically approximately a quarter turn / 90 degrees for a bayonet mount) until you feel or hear it click into the locked position. Confirm the exact rotation direction and angle against Aston Martin service documentation. If clip-retained: push the switch straight into the bracket until the retaining clips engage with an audible click. Gently tug on the switch body to confirm it is securely locked in the bracket.
6. 6

   Reconnect the electrical connector
   Take the electrical connector and align it with the terminals on the new brake light switch. Push the connector straight onto the switch until you hear or feel the locking tab engage with a positive click. Gently pull on the connector to verify it is securely locked. Ensure the wiring harness has adequate slack and is not pinched or stressed.
7. 7

   Verify switch adjustment and pedal clearance
   With the switch installed, visually verify that the brake pedal arm makes proper contact with the switch plunger when the pedal is at rest (not depressed). There should be minimal gap between the pedal arm and switch contact point. When you press the brake pedal by hand, verify that the plunger or contact element moves freely and the pedal returns smoothly to its rest position without binding on the switch. The switch should actuate immediately when the pedal is depressed, with no excessive free play.

Reassembly

1. Return the driver's seat to the operator's preferred position
2. Close the driver's door

Verification

• Turn the ignition to the ON position (engine does not need to be started)
• Have an assistant observe the rear brake lights while you press and release the brake pedal, OR position a mirror or use a mobile phone camera to observe the brake lights yourself
• Verify that both brake lights illuminate immediately when the brake pedal is depressed and extinguish when the pedal is released
• Test multiple times, pressing the pedal slowly and quickly, to confirm consistent brake light operation
• If equipped with a third center high-mount brake light (CHMSL), verify it also illuminates with the brake lights
• Start the engine and verify that the transmission shift interlock allows shifting out of Park only when the brake pedal is depressed
• If equipped with cruise control, drive the vehicle in a safe area and verify that engaging the brake pedal immediately disengages cruise control
• If any brake lights do not illuminate, or if shift interlock or cruise control do not function properly, recheck the electrical connector engagement and switch installation before driving

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