This procedure covers the removal and replacement of a failed HID (High-Intensity Discharge) headlight ballast on a 2015-2020 Ford F-150 with 3.5L EcoBoost engine.

Warnings

Tools required

Parts

• HID Ballast (specify driver or passenger side) × 1 — Use OEM Ford specification or verified aftermarket
• Zip ties or wire loom clips × 2 — Generic replacement if originals damaged

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off all lights and remove key from ignition
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal and wait 5 minutes for HID system capacitors to fully discharge
5. Identify which ballast has failed (driver or passenger side) by visual inspection or previous diagnosis
6. Allow headlight assembly to cool completely if vehicle was recently driven

Procedure

1. 1

   Remove headlight access cover
   Locate the circular or rectangular access cover on the rear of the headlight assembly in the engine bay. Rotate counterclockwise approximately 1/4 turn or pull retaining tabs to remove the dust cover. Set aside in clean location.
2. 2

   Disconnect HID bulb connector
   Locate the HID bulb connector at the back of the headlight assembly. Press the locking tab and pull straight back to disconnect the wiring harness from the bulb. Do not twist or pull on the wires themselves.
3. 3

   Locate the HID ballast
   The HID ballast is typically mounted on the inner fender well or on a bracket near the headlight assembly. Follow the wiring harness from the headlight to locate the rectangular ballast module. On the driver side, it may be behind the battery; on passenger side, it may be near the air filter housing.
4. 4

   Disconnect ballast electrical connectors
   Identify the input connector (from vehicle wiring harness) and output connector (to HID bulb). Press the locking tabs on both connectors and pull straight out to disconnect. Note the orientation of connectors for reassembly.
5. 5

   Remove ballast mounting hardware
   Remove the ballast mounting bolts using an 8mm or 10mm socket depending on configuration. Most F-150 ballasts use two mounting bolts. Support the ballast while removing the final bolt to prevent it from falling.
   Torque spec

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

   Remove failed ballast
   Carefully maneuver the ballast out of its mounting location. If wiring is secured with zip ties or clips to the ballast bracket, cut or release these to free the ballast completely. Inspect the mounting bracket for damage or corrosion.
7. 7

   Prepare new ballast for installation
   Remove new ballast from packaging. Verify it matches the failed unit in connector types and mounting configuration. If applicable, transfer any mounting brackets from old ballast to new unit. Check that all connector seals are properly seated.
8. 8

   Install new ballast
   Position new ballast in mounting location, ensuring wiring harnesses route properly without sharp bends or pinch points. Align mounting holes and hand-thread mounting bolts. Torque bolts to specification using torque wrench, alternating between bolts for even pressure.
   Torque spec

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

   Connect electrical connectors
   Connect the input connector from vehicle harness to ballast input port, ensuring it clicks into place. Connect the output connector from ballast to HID bulb connector, again verifying positive engagement. Apply small amount of dielectric grease to connectors if available to prevent corrosion.
10. 10

    Secure wiring harness
    Route wiring harness away from hot engine components, sharp edges, and moving parts. Secure with new zip ties or wire loom clips to existing mounting points. Ensure no wires are stretched tight or hanging loose.
11. 11

    Reinstall headlight access cover
    Align access cover with headlight housing and rotate clockwise to lock in place, or press until retaining tabs click. Ensure cover is fully seated to prevent moisture intrusion into headlight assembly.
12. 12

    Reconnect battery and test
    Reconnect negative battery terminal and torque terminal bolt to specification. Turn ignition to ON position and activate headlights. Verify the repaired HID bulb illuminates properly with no flickering. Check that both low and high beam functions operate correctly.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all electrical connectors are fully seated and locked
2. Verify wiring harness is secured and routed away from heat sources and moving components
3. Confirm headlight access cover is properly installed to maintain weatherproof seal
4. Double-check that no tools or parts were left in engine bay

Verification

• Start engine and verify no warning lights on instrument cluster related to lighting system
• Test headlights in low beam mode - both headlights should illuminate with consistent color and brightness
• Test high beam mode - verify proper operation of both headlights
• If equipped, test automatic headlight leveling system by observing beam pattern adjustment
• Turn off headlights and visually inspect for any abnormal glow or arcing around ballast area
• Take a short test drive after dark to confirm proper illumination and aim
• Monitor for any flickering or shutdown during first few drive cycles, as this may indicate incorrect ballast specification or poor connection

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