This procedure covers the replacement of a failed HID ballast on a 2018-2024 Toyota Camry with 2.5L I4 engine, requiring removal of the headlight assembly to access the ballast module.

Warnings

Tools required

Parts

• HID Ballast (specify left or right side) × 1 — Use OEM specification or verify aftermarket compatibility
• Dielectric grease × 1 — For electrical connectors

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn ignition off and remove key
3. Open hood and secure with prop rod
4. Disconnect negative battery terminal and wait minimum 3 minutes for HID system capacitor discharge
5. Allow headlights to cool completely if recently operated (minimum 10 minutes)
6. Identify which side (driver or passenger) requires ballast replacement

Procedure

1. 1

   Remove upper radiator cover clips
   Locate the plastic clips securing the upper radiator cover panel above the headlight assembly. Using a flathead screwdriver or trim tool, carefully pry up the center pin of each clip approximately 5mm, then pull the entire clip upward to remove. Remove all clips along the section above the affected headlight. Set clips aside in a container to prevent loss.
2. 2

   Remove headlight assembly mounting bolts
   Locate the two 10mm mounting bolts securing the headlight assembly. One bolt is typically located at the top outer corner of the headlight, and one toward the inner/upper area near the grille. Using a 10mm socket and ratchet, remove both mounting bolts completely. Keep bolts organized for reinstallation.
3. 3

   Disconnect headlight wiring harness
   Reach behind the headlight assembly and locate the main wiring harness connector. Press the release tab on the connector while pulling it straight back from the headlight assembly. Do not pull on wires. If connector is stiff, gently wiggle while maintaining pressure on release tab. Set connector aside in a clean area.
4. 4

   Remove headlight assembly
   With bolts removed and harness disconnected, carefully pull the headlight assembly forward and outward from the vehicle. The assembly is retained by alignment tabs at the bottom and inner edge. Apply gentle, even pressure while angling the outer edge forward first, then work the entire assembly free from the mounting tabs. Place headlight assembly on a clean, padded surface with lens facing up.
5. 5

   Access HID ballast
   With the headlight assembly removed, locate the HID ballast mounted on the rear of the headlight housing. The ballast is typically a rectangular metal or plastic module attached with mounting bolts or integrated clips. Identify the high-voltage connector leading from the ballast to the HID bulb and the input power connector from the vehicle harness.
6. 6

   Disconnect ballast electrical connectors
   Locate the input power connector and the high-voltage output connector on the ballast. For each connector, press the release tab and pull straight out. The high-voltage connector to the HID bulb may have a locking collar that requires counterclockwise rotation before removal. Note connector orientations for proper reassembly. Inspect connectors for corrosion, melting, or damage.
   ⚠Even with battery disconnected, residual voltage may be present. Handle connectors by the plastic housing only, never by exposed terminals.
7. 7

   Remove ballast mounting hardware
   Identify the mounting method for the ballast. Most are secured with two or three small bolts or screws. Using appropriate socket or screwdriver, remove all mounting hardware. If ballast uses bracket-style mounting, remove the bracket bolts. Note the exact mounting orientation and any spacers or washers for correct reinstallation of the new ballast.
   ℹ️Some ballasts use integrated clips instead of bolts. These require sliding or rotating the ballast to release from mounting tabs.
   Torque spec

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

   Remove failed ballast and inspect
   Remove the failed ballast from the headlight assembly. Inspect the mounting area for any signs of water intrusion, corrosion, or heat damage. Check that the rubber seal or grommet at the ballast mounting location is intact. Inspect the HID bulb and igniter (if separate) for any signs of damage. Clean mounting surfaces if any debris or corrosion is present.
9. 9

   Install new HID ballast
   Position the new ballast in the exact orientation as the original, ensuring any alignment tabs or pins are properly seated. Install mounting hardware and tighten fasteners evenly to avoid stressing the ballast housing. If using bracket mounting, ensure bracket is properly aligned before tightening. Verify the ballast sits flush and secure without movement.
   ⚠Do not overtighten ballast mounting bolts as this can crack the ballast housing or damage mounting tabs on the headlight assembly.
   Torque spec

   Module Mounting Bolts8 Nm (6 lb-ft)
10. 10

    Reconnect ballast electrical connectors
    Apply a small amount of dielectric grease to the contact areas of both connectors to prevent corrosion. Connect the input power connector from the vehicle harness to the ballast, ensuring it clicks fully into place. Connect the high-voltage output connector to the HID bulb/igniter, rotating any locking collar clockwise until secure. Gently tug each connector to verify positive engagement.
11. 11

    Reinstall headlight assembly
    Position the headlight assembly near its mounting location. Align the bottom and inner mounting tabs with their corresponding slots in the vehicle body. Angle the assembly into place, ensuring tabs are fully seated before pushing the assembly flush with surrounding body panels. The assembly should sit evenly with consistent gaps around all edges.
12. 12

    Secure headlight assembly
    Insert and hand-tighten both 10mm mounting bolts to secure the headlight assembly. Ensure the assembly remains properly aligned and seated before final tightening. Reconnect the main headlight wiring harness, pressing firmly until the connector clicks into place. Verify proper engagement by gently pulling on the connector body.
13. 13

    Reinstall radiator cover
    Position the upper radiator cover panel over the headlight area. Insert each plastic clip into its corresponding hole, pressing the outer portion down first. Then press the center pin down firmly until it is flush with the clip body, securing the panel. Verify all clips are fully engaged and the panel sits flush.
14. 14

    Reconnect battery and test
    Reconnect the negative battery terminal and tighten the terminal bolt to specification. Turn the ignition to the ON position without starting the engine. Turn on the headlights and verify the HID system on the repaired side illuminates properly. HID bulbs may take 5-10 seconds to reach full brightness and may flicker briefly during warm-up. Observe for any error messages on the instrument cluster.
    ⚠Do not look directly at HID bulbs when testing. HID lights produce intense ultraviolet radiation that can cause eye damage.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all electrical connectors are fully seated with positive engagement
2. Verify headlight assembly is properly aligned with consistent panel gaps before final testing
3. Check that all radiator cover clips are secure to prevent panel vibration or detachment

Verification

• With engine off and headlights on, verify both low beam and high beam functions operate correctly on the repaired side
• Observe HID bulb through the headlight lens to confirm stable operation without flickering after initial warm-up period
• Check instrument cluster for any headlight-related warning lights or error messages
• Perform a night test drive to verify proper beam pattern and intensity compared to the opposite headlight
• Inspect headlight assembly installation to ensure no gaps or misalignment that could allow water intrusion

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