This procedure covers the removal and replacement of the interior fuse box (Battery Junction Box) located under the driver-side dashboard on 2015-2020 Ford F-150 trucks with the 3.5L EcoBoost V6 engine.

Warnings

Tools required

Parts

• Interior fuse box assembly (Battery Junction Box) × 1 — Use OEM specification
• Trim panel retaining clips × 1 — As needed for damaged clips

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key/fob from vehicle
3. Disconnect negative battery terminal and secure cable away from battery post
4. Wait minimum 2 minutes for electrical system capacitors to discharge
5. Adjust steering wheel to lowest position for improved access
6. Take detailed photos of fuse box orientation and all connected harnesses

Procedure

1. 1

   Remove lower dash panel
   Locate the lower dash trim panel beneath the steering column on the driver side. Remove the two 7mm screws securing the panel. Carefully pull the panel away from the dashboard, releasing the plastic retaining clips. Disconnect any electrical connectors for the OBD-II port or hood release if equipped with electronic release.
2. 2

   Access fuse box mounting area
   With the lower panel removed, locate the interior fuse box mounted to the left side of the steering column support bracket. The fuse box is a black rectangular module with multiple wire harness connectors on the back. Use a flashlight to identify all mounting bolts and electrical connections.
3. 3

   Remove fuse box cover
   Press the release tabs on both sides of the fuse box cover and remove it. Set aside the cover with any fuses or relays still installed. Document or photograph the fuse/relay positions if needed for reference.
4. 4

   Disconnect primary wire harness connectors
   Locate the main wire harness connectors on the rear of the fuse box. There are typically 3-5 large multi-pin connectors. Press the locking tabs and carefully pull each connector straight out from the fuse box. Do not twist or bend connectors during removal. Mark each connector position with tape and numbering if not already color-coded.
5. 5

   Disconnect battery feed cable
   Locate the large battery positive cable terminal connected to the fuse box (typically red or orange wire with a protective boot). Remove the protective boot. Use a 10mm socket to loosen and remove the terminal bolt securing the battery cable to the fuse box. Carefully pull the cable terminal away from the fuse box.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
6. 6

   Remove ground connections
   Locate any ground strap connections on or near the fuse box mounting bracket. Use a 10mm socket to remove the ground strap bolts. Note the orientation and stacking order of ground straps, washers, and terminals for correct reassembly.
   ℹ️Ground connections must be clean and free of corrosion for proper electrical system operation
   Torque spec

   Ground Strap Bolts12 Nm (9 lb-ft)
7. 7

   Remove fuse box mounting bolts
   Locate the mounting bolts securing the fuse box to the dashboard support bracket. Typically there are 2-3 bolts accessible from the front and side of the fuse box. Use a 10mm socket to remove all mounting bolts. Support the fuse box while removing the final bolt.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
8. 8

   Remove fuse box assembly
   Carefully maneuver the fuse box out of the mounting area. Work slowly and check for any remaining wire connections or mounting points. The fuse box may need to be tilted or rotated to clear surrounding components. Once all connections are confirmed disconnected, remove the fuse box from the vehicle.
9. 9

   Prepare new fuse box
   Inspect the new fuse box for any shipping damage. Compare the connector configuration with the removed unit to confirm correct part. Transfer any fuses, relays, or modules from the old fuse box to the new unit in their exact original positions. If reusing the old fuse box after repair, clean all connector pins with electrical contact cleaner and allow to dry.
10. 10

    Install fuse box assembly
    Position the new or repaired fuse box into the mounting location, carefully routing it past surrounding components. Align the mounting holes with the dashboard support bracket. Install mounting bolts hand-tight, then torque to specification using a torque wrench. Ensure the fuse box sits flush against the mounting surface.
    Torque spec

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

    Reconnect ground connections
    Clean the ground connection points on the mounting bracket with a wire brush or sandpaper to ensure bare metal contact. Reinstall ground straps in their original positions with washers and bolts. Torque ground strap bolts to specification.
    Torque spec

    Ground Strap Bolts12 Nm (9 lb-ft)
12. 12

    Reconnect battery feed cable
    Clean the battery cable terminal and fuse box connection point if needed. Position the battery positive cable terminal onto the fuse box stud. Install the terminal bolt and torque to specification. Do not overtighten as this can damage the fuse box terminal. Reinstall the protective boot over the connection.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
13. 13

    Reconnect wire harness connectors
    Using your photos or labels as reference, reconnect all wire harness connectors to the fuse box in their correct positions. Push each connector firmly until the locking tab clicks into place. Verify each connection is fully seated by gently pulling on the connector body.
14. 14

    Reinstall fuse box cover and trim panel
    Snap the fuse box cover back onto the fuse box assembly. Reconnect any electrical connectors for the OBD-II port or hood release. Position the lower dash panel and press it into place to engage the retaining clips. Install the two 7mm panel screws.
15. 15

    Reconnect battery and initialize systems
    Reconnect the negative battery terminal and torque the terminal bolt to specification. Do not overtighten. Turn the ignition to the ON position without starting the engine and check for warning lights. Start the engine and verify all electrical systems are functioning. Check for diagnostic trouble codes with a scan tool if available.
    ⚠Battery terminal bolts must be torqued correctly - overtightening can crack the battery terminal
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all wire harness connectors are fully seated and locked
2. Verify fuse box mounting bolts are torqued to specification to prevent electrical issues from vibration
3. Check that ground connections are clean and tight for proper system operation
4. Confirm fuse box cover is properly installed to protect internal components

Verification

• Turn ignition to ON position and verify all dashboard warning lights illuminate and then extinguish normally
• Start engine and verify proper operation of all electrical systems including headlights, wipers, power windows, climate control, and radio
• Test turn signals, brake lights, and hazard lights for proper function
• Operate power seats, mirrors, and door locks to confirm all circuits are functioning
• Use a scan tool to check for diagnostic trouble codes related to electrical system or modules
• Verify no warning lights remain illuminated on the instrument cluster
• Test that clock, radio presets, and seat positions need to be reset (confirms proper battery disconnect procedure was followed)

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