This procedure covers the removal and replacement of the interior fuse box (also called the Body Control Module or Smart Junction Box) located under the driver's side dashboard on 2021-2024 Ford F-150 vehicles.

Warnings

Tools required

Parts

• Interior fuse box assembly (Smart Junction Box) × 1 — Use OEM specification
• Panel clips (assorted) × 1 — Replacement clips if broken during removal

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key fob from vehicle interior
3. Open driver's door and lower the driver's side window
4. Photograph or document all fuse positions in the interior fuse box
5. Disconnect negative battery terminal and secure cable away from battery post
6. Wait minimum 2 minutes for system capacitors to discharge
7. Gather all necessary tools and new fuse box assembly

Procedure

1. 1

   Disconnect battery
   Disconnect the negative battery terminal using a 10mm socket. Secure the cable away from the battery post to prevent accidental reconnection. Wait at least 2 minutes before proceeding.
   Torque spec

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

   Remove lower dashboard panel
   Remove the lower dashboard trim panel below the steering column. Use panel removal tools to carefully release the retaining clips starting from the bottom edge and working upward. There are typically 6-8 clips securing this panel. Set panel aside in a safe location.
3. 3

   Remove fuse box cover
   Locate the interior fuse box on the left side of the dashboard. Remove the fuse box cover by pressing the release tabs and pulling outward. Remove any fuses that will interfere with fuse box removal and document their positions.
   Torque spec

   Cover Screws12 Nm (9 lb-ft)
4. 4

   Disconnect electrical connectors
   There are multiple large multi-pin connectors on the back and sides of the fuse box. Each connector has a different colored release mechanism. Carefully depress the locking tabs while pulling the connectors straight out. Do not rock or twist connectors. Document the position and orientation of each connector with photos. Expect 4-6 large connectors depending on vehicle configuration.
   ⚠Some connectors have secondary locks that must be moved to the unlock position before the primary lock will release
5. 5

   Remove ground connections
   Locate and remove the ground strap bolts connecting the fuse box to the vehicle chassis. There are typically 1-2 ground connections. Clean the contact surfaces if reinstalling the same unit.
   Torque spec

   Ground Strap Bolt16 Nm (12 lb-ft)
6. 6

   Remove mounting bolts
   Remove the fuse box mounting bolts using a 10mm socket. There are typically 3-4 mounting bolts securing the assembly to the dashboard structure. Note the position and length of each bolt as they may vary.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
7. 7

   Remove fuse box assembly
   Carefully maneuver the fuse box assembly out of its mounting location. The unit may need to be tilted and rotated to clear the dashboard structure and steering column. Be careful not to damage any remaining connected wiring harnesses or surrounding components.
8. 8

   Prepare new fuse box
   If installing a new fuse box, inspect all connector ports for shipping plugs or protective covers and remove them. Verify the new unit matches the original part number and configuration. Transfer all necessary fuses from the old unit to the new unit in their documented positions.
9. 9

   Install fuse box assembly
   Position the new or serviced fuse box into the mounting location, carefully maneuvering it past the steering column and dashboard structure. Align the mounting holes with the dashboard bracket.
10. 10

    Install mounting bolts
    Install all fuse box mounting bolts finger-tight first, then torque to specification in a cross-pattern to ensure even seating of the assembly.
    Torque spec

    Module Mounting Bolts8 Nm (6 lb-ft)
11. 11

    Reconnect ground connections
    Reconnect all ground strap bolts. Ensure contact surfaces are clean and free of corrosion, paint, or debris for proper electrical connection. Torque to specification.
    Torque spec

    Ground Strap Bolt16 Nm (12 lb-ft)
12. 12

    Reconnect electrical connectors
    Reconnect all electrical connectors to the fuse box in their documented positions. Each connector should click firmly into place. Ensure secondary locks are engaged where applicable. Verify each connector is fully seated by attempting to pull it out gently.
    ⚠Cross-threading or forcing connectors can damage pins and cause electrical faults
13. 13

    Install fuse box cover and panels
    Reinstall the fuse box cover, ensuring all tabs engage properly. Reinstall the lower dashboard panel by aligning the clips and pressing firmly until each clip clicks into place. Install cover screws if applicable and torque to specification.
    Torque spec

    Cover Screws12 Nm (9 lb-ft)
14. 14

    Reconnect battery
    Reconnect the negative battery terminal and torque to specification. Do not overtighten as this can damage the battery terminal.
    ⚠Vehicle may exhibit multiple warning lights and fault codes until module is programmed
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all panel clips are fully engaged and panels are flush with surrounding trim
2. Verify fuse box cover is properly secured and all fuses are correctly positioned
3. Check that no tools or parts were left in the dashboard area

Verification

• Turn ignition to ON position (do not start) and verify dash illuminates without unusual warning lights beyond those expected for unprogrammed module
• Using Ford IDS or equivalent professional scan tool, perform module programming and configuration according to Ford service procedures
• After programming, clear all diagnostic trouble codes
• Test all electrical systems controlled by the interior fuse box including lights, windows, wipers, HVAC controls, and accessory power outlets
• Verify no warning lights remain illuminated on instrument cluster
• Test power windows, door locks, and other body control functions from both driver and passenger positions
• Perform a complete system scan with diagnostic tool to verify no communication faults exist

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