Fuse Box - Engine Bay

Remove and replace the engine bay fuse box assembly on a 2009 Aston Martin DB9, including disconnection of wiring harnesses and mounting hardware.

Warnings

Tools required

Parts

• Engine bay fuse box assembly × 1 — Use OEM specification
• Fuse box cover seal (if damaged) × 1 — Use OEM specification

Preparation

1. Park vehicle on level surface and engage parking brake
2. Ensure engine is completely cool
3. Open hood and secure in raised position
4. Place fender cover over driver's side fender to protect paintwork
5. Photograph the engine bay fuse box location and all visible connections
6. Have replacement fuse box available and verify correct part number against VIN

Procedure

1. 1

   Disconnect battery negative terminal
   Locate the battery in the rear trunk (boot) compartment; verify exact location and access against OEM service documentation for this VIN. Using the appropriate socket (verify size against OEM documentation), loosen the negative battery terminal bolt and disconnect the cable. Secure the cable away from the terminal post to prevent accidental reconnection. Note: Locate the battery in the rear trunk compartment (verify exact side against the vehicle's owner manual, as DB9 battery placement can vary). Note: Locate the battery in the rear trunk (boot) compartment; verify exact location and access panel against OEM documentation for this VIN.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
2. 2

   Wait for system power-down
   Wait at least 5 minutes after battery disconnection to allow all capacitors in the electrical system to discharge and for control modules to fully power down. This prevents damage to sensitive electronics during fuse box removal.
3. 3

   Remove fuse box cover
   Locate the engine bay fuse box in the engine compartment (verify exact position against OEM service documentation for the 2009 DB9). Release the retaining clips on the fuse box cover by pressing the tabs and lift the cover straight up to remove. The cover has an integrated seal that may need gentle prying with a trim tool if stuck. Note: Locate the engine bay fuse box in the engine compartment; verify its exact position and side against OEM documentation for this vehicle before proceeding.
4. 4

   Document fuse layout
   Before removing any fuses, photograph the complete fuse layout or create a diagram showing which fuses are installed in each position and their amperage ratings. The fuse box cover should have a legend, but verify against actual installed fuses as previous owners may have made changes.
5. 5

   Remove all fuses and relays
   Using the integrated fuse puller or needle-nose pliers, carefully remove all fuses and relays from the fuse box. Place them in a labeled container or on a diagram matching their original positions. This prevents damage to the fuses during fuse box removal and ensures correct reinstallation.
6. 6

   Disconnect primary wiring harness connectors
   Locate the main wiring harness connectors on the underside and rear of the fuse box. There are multiple large multi-pin connectors that supply power and signals to the fuse box; verify the exact count and configuration against DB9 service documentation before disconnecting. Press the locking tabs on each connector and carefully pull straight back to disconnect. The connectors use secondary locks that must be released before the primary latch will disengage. Note: There are multiple large multi-pin connectors that supply power and signals to the fuse box; verify the exact count and configuration against OEM service documentation before disconnecting. Note: There are multiple large multi-pin connectors that supply power and signals to the fuse box; confirm the exact number and configuration against OEM documentation for this vehicle.
7. 7

   Release harness support bracket
   Identify the wiring harness support bracket that secures the main harness to the fuse box mounting area. Remove the Torx fasteners securing this bracket. Verify the exact number of fasteners holding the bracket in place against OEM service documentation before removal. Set the bracket aside but keep fasteners with it for reassembly. Note: Verify the exact number and size of Torx fasteners holding the bracket in place against DB9 service documentation before removal. Note: Confirm the exact number and size of Torx fasteners holding the bracket in place against OEM documentation for this vehicle.
8. 8

   Remove fuse box mounting fasteners
   Locate and remove the fuse box mounting fasteners. The fuse box is secured to the mounting structure with mounting bolts accessed from the top and sides of the assembly. Verify the exact bolt count and head size against OEM service documentation. Support the fuse box with one hand while removing the final fasteners to prevent it from dropping. Note: The fuse box is secured to the inner fender structure with mounting bolts accessed from the top and sides of the assembly. Verify the exact bolt count and head size against DB9 service documentation before removal. Note: The fuse box is secured to the mounting structure with mounting bolts; confirm the exact count, head size, and access points against OEM documentation for this vehicle before removal.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
9. 9

   Inspect mounting points and grounding
   With the fuse box removed, inspect the mounting surface for corrosion or damage. Check the ground connection points on the inner fender structure. Clean any corrosion from the mounting surface and ground points using a wire brush. Ensure all ground straps are in good condition and connections are clean and tight.
10. 10

    Position new fuse box
    Position the replacement fuse box into the mounting location, ensuring proper alignment with all mounting holes and connector access. Guide the unit carefully to avoid pinching any wiring harnesses. Verify that the fuse box seats fully against the mounting surface before installing fasteners.
11. 11

    Install mounting fasteners
    Install all fuse box mounting bolts hand-tight first to ensure proper alignment (verify exact bolt count against OEM service documentation). Once all bolts are started, torque them to the OEM-specified value (verify against service documentation; small housing fasteners are typically low torque) in a cross-pattern sequence to ensure even mounting pressure. This prevents warping of the fuse box housing. Note: Once all bolts are started, torque them to the DB9 manufacturer-specified value in a cross-pattern sequence to ensure even mounting pressure. Verify the correct torque spec against service documentation before final tightening. Note: Install all fuse box mounting bolts hand-tight first to ensure proper alignment. Once all bolts are started, torque them to the OEM-specified value in a cross-pattern sequence to ensure even mounting pressure.
    Torque spec

    Module Mounting Bolts8 Nm (6 lb-ft)
12. 12

    Reinstall harness support bracket
    Position the wiring harness support bracket back onto its mounting location and install the Torx fasteners. Ensure the harness sits properly in any routing clips or channels before fully tightening the bracket fasteners.
13. 13

    Reconnect wiring harness connectors
    Reconnect all main wiring harness connectors to the fuse box in reverse order of removal (verify exact count and configuration against OEM service documentation). Push each connector firmly until you hear and feel the primary latch engage, then verify the secondary lock is properly seated. Gently tug on each connector to confirm it is securely locked.
14. 14

    Install fuses and relays
    Using your documentation from disassembly, reinstall all fuses and relays into their correct positions. Ensure each fuse is fully seated in its socket. Verify that all amperage ratings match the fuse box legend and your documentation. Do not substitute different amperage fuses.
15. 15

    Reinstall fuse box cover
    Inspect the fuse box cover seal for damage and replace if necessary. Align the cover over the fuse box and press down firmly until all retaining clips engage with an audible click. Verify the cover is secure and the seal is properly seated all around.
16. 16

    Reconnect battery
    Return to the rear trunk and reconnect the negative battery terminal. Torque the terminal bolt to the OEM manufacturer-specified value (battery terminal clamps are typically low torque; verify against OEM service documentation to avoid damaging the post or terminal). Do not overtighten as this can damage the battery post or terminal. Note: Torque the terminal bolt to the OEM-specified value (battery terminal clamps are typically low torque, around 5-6 Nm); verify against OEM documentation and do not overtighten.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all wiring harness connectors are fully seated and locked before reconnecting the battery
2. Verify the fuse box cover is properly installed with all clips engaged
3. Double-check that all fuses are installed in their correct positions per the documentation created during disassembly
4. Route all wiring harnesses in their original paths to avoid interference with moving components

Verification

• Turn ignition to position II (without starting engine) and verify the instrument cluster illuminates normally
• Check that all warning lights perform their bulb check as expected
• Start the engine and verify normal operation with no warning lights
• Test all electrical systems controlled by the engine bay fuse box: headlights, cooling fans, fuel pump operation (listen for pump prime), ABS system, and engine management functions
• Use a multimeter to verify voltage at key fuse positions matches expected values (typically 12V+ on ignition-switched circuits)
• Verify no electrical faults are stored using a diagnostic scanner
• Ensure fuse box cover is secure and properly sealed to prevent water intrusion

Related trouble codes on this vehicle

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