This procedure covers the removal and replacement of the engine bay fuse box (Battery Junction Box/BJB) on a 2015-2020 Ford F-150 with 5.0L V8 Coyote engine.

Warnings

Tools required

Parts

• Engine bay fuse box assembly (Battery Junction Box) × 1 — Use OEM Ford part number
• Fuse box mounting hardware kit × 1 — Often included with fuse box

Preparation

1. Park vehicle on level ground and engage parking brake
2. Turn ignition off and remove key. Wait at least 2 minutes for modules to power down
3. Open hood and secure with prop rod
4. Photograph the fuse box from multiple angles showing all connector positions and wire routing
5. Label each electrical connector with tape and marker before removal to aid reinstallation

Procedure

1. 1

   Disconnect battery negative terminal
   Using a 10mm socket, loosen the negative battery terminal bolt. Remove the negative cable from the battery post and secure it away from the battery to prevent accidental contact during the repair.
   Torque spec

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

   Disconnect battery positive terminal
   Using a 10mm socket, loosen the positive battery terminal bolt. Remove the positive cable from the battery post. The fuse box is mounted directly to the positive battery cable, so this cable will remain attached to the fuse box assembly.
   ⚠The positive cable remains energized from the battery side. Ensure it does not contact ground or the negative terminal.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)
3. 3

   Remove fuse box cover
   Release the cover clips on the sides of the fuse box cover by pressing the tabs and lifting upward. Remove the cover to expose all fuses and relays. Set cover aside in a clean location.
4. 4

   Disconnect primary electrical connectors
   Locate the large multi-pin connectors on the bottom and sides of the fuse box (typically 3-4 main connectors). Press the locking tabs and carefully disconnect each connector. Use a small flathead screwdriver to release stubborn connector locks if necessary. Ensure you reference your photos for correct identification.
   ⚠Do not force connectors. Locking tabs must be fully released before pulling. Damaged connectors can cause multiple electrical faults.
5. 5

   Disconnect auxiliary connectors and ground straps
   Disconnect any remaining smaller connectors attached to the fuse box. Using an 8mm or 10mm socket, remove ground strap bolts connecting to the fuse box mounting bracket. Clean the ground contact surfaces with a wire brush.
   Torque spec

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

   Remove fuse box mounting bolts
   Locate the fuse box mounting bolts securing the assembly to the inner fender/frame rail (typically 2-3 bolts). Using a 10mm socket with extension, remove all mounting bolts. Keep bolts organized for reinstallation.
   Torque spec

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

   Remove positive battery cable from fuse box
   The positive battery cable connects to the fuse box with terminal bolts or bracket bolts. Using an 8mm socket, remove the cable connection hardware. Note the exact orientation and stacking order of any washers or spacers.
   ⚠Keep track of washer and spacer orientation. Incorrect reassembly can cause poor electrical contact and voltage drops.
   Torque spec

   Battery Terminal Bolts6 Nm (4 lb-ft)

   Bracket Bolts26 Nm (19 lb-ft)
8. 8

   Remove old fuse box assembly
   Carefully lift the fuse box assembly out of the engine bay. Maneuver it around any obstruction while being mindful of any remaining wire harnesses. Set the old fuse box on a clean workbench.
9. 9

   Transfer fuses and relays to new fuse box
   Remove all fuses and relays from the old fuse box and install them in the corresponding positions in the new fuse box. Reference the fuse box diagram on the cover or in the owner's manual. Inspect each fuse for damage or corrosion before transferring.
   ⚠Fuses and relays must be installed in the exact same positions. Incorrect placement can damage vehicle systems or cause no-start conditions.
10. 10

    Position new fuse box assembly
    Position the new fuse box in the engine bay, routing it carefully around any harnesses or brackets. Align the mounting holes with the frame rail/inner fender mounting points.
11. 11

    Install positive battery cable to fuse box
    Connect the positive battery cable to the new fuse box terminal, ensuring all washers and spacers are in the correct order and orientation. Hand-start the terminal bolts or bracket bolts, then torque to specification.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

    Bracket Bolts26 Nm (19 lb-ft)
12. 12

    Install fuse box mounting bolts
    Install all fuse box mounting bolts finger-tight first, ensuring proper alignment. Once all bolts are started, torque each mounting bolt to specification in a cross-pattern to ensure even clamping.
    Torque spec

    Module Mounting Bolts8 Nm (6 lb-ft)
13. 13

    Reconnect ground straps
    Reconnect all ground straps to the fuse box mounting bracket. Ensure contact surfaces are clean and free of paint or corrosion. Install ground strap bolts and torque to specification.
    Torque spec

    Ground Strap Bolt16 Nm (12 lb-ft)
14. 14

    Reconnect all electrical connectors
    Reconnect all electrical connectors to the fuse box, referencing your photos and labels. Each connector should click firmly into place. Verify locking tabs are fully engaged on each connector. Apply dielectric grease to connector seals if desired.
    ⚠Each connector has a unique keying to prevent incorrect installation, but verify against photos. An incorrectly connected harness can cause immediate electrical damage when battery is reconnected.
15. 15

    Reconnect battery terminals
    Reconnect the positive battery terminal first, then the negative terminal. Torque both battery terminal bolts to specification. Do not overtighten as this can damage the battery posts.
    ⚠Always connect positive first, then negative. This prevents sparking if a tool contacts ground during installation.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)
16. 16

    Install fuse box cover and perform system check
    Install the fuse box cover by aligning the tabs and pressing down until all clips engage. Turn the ignition to ON position (do not start) and verify the instrument cluster illuminates normally with no unusual warning lights. Start the engine and verify normal operation.

Reassembly

1. After reconnecting the battery, the vehicle will need to relearn idle and transmission shift patterns over the next 20-30 miles of driving
2. Radio presets, clock, and seat memory positions will need to be reprogrammed
3. If equipped, power windows may need to be re-initialized by fully rolling each window down, then up, and holding the switch for 2 seconds at the top position
4. Some vehicles may require throttle body relearn procedure: key on for 10 seconds, key off for 10 seconds, repeat 3 times

Verification

• Turn ignition to ON (engine off) and verify all warning lights perform bulb check normally, then extinguish as expected
• Start engine and verify it runs smoothly with no warning lights
• Test all major electrical systems: headlights, turn signals, brake lights, horn, power windows, HVAC blower, and wipers
• With engine running, use a multimeter to verify charging voltage at battery terminals (13.8-14.4V typical)
• Take a short test drive to verify all systems function normally and no new warning lights appear
• Verify all fuses are properly seated and the fuse box cover is securely latched

More procedures for this vehicle