Replace the HID ballast module that controls the high-intensity discharge headlight bulb operation on one side of the vehicle.

Warnings

Tools required

Parts

• HID ballast module × 1 — Use OEM specification - Toyota 85967-02xxx series

Preparation

1. Park vehicle on level surface and engage parking brake
2. Turn off headlights and all electrical accessories
3. Allow HID system to cool for at least 10 minutes if recently operated
4. Open hood and secure with prop rod
5. Identify which side (left or right) has the failed ballast

Procedure

1. 1

   Disconnect battery negative terminal
   Using a 10mm wrench, loosen and remove the negative battery terminal. Secure the cable away from the battery post. Wait a minimum of 3 minutes to allow HID system capacitors to fully discharge.
   Torque spec

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

   Remove headlight assembly access cover
   Locate the plastic access cover on the back of the headlight housing. Rotate the cover counterclockwise approximately 1/4 turn and pull it straight back to remove. This provides access to the bulb and ballast area.
3. 3

   Disconnect HID bulb connector
   Locate the HID bulb electrical connector at the back of the headlight assembly. Press the release tab and carefully pull the connector straight out from the bulb. Do not pull on the wires themselves.
4. 4

   Locate HID ballast module
   The HID ballast is mounted on the headlight assembly housing or on the inner fender well near the headlight. On 2014-2019 Corollas, it is typically a rectangular aluminum or plastic module with heat sink fins, approximately 4x3 inches, connected by a high-voltage cable to the HID bulb.
5. 5

   Disconnect ballast electrical connectors
   Identify two connectors on the ballast: the input power connector (from vehicle wiring harness) and the high-voltage output connector (to HID bulb). Press the release tabs on each connector and carefully disconnect both. Note their positions for reassembly.
6. 6

   Remove ballast mounting bolts
   Using an 8mm socket, remove the mounting bolts securing the ballast to the headlight assembly or mounting bracket. Most Corolla HID 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)
7. 7

   Remove failed ballast
   Once all bolts and connectors are removed, carefully extract the ballast module from the engine bay. Inspect the mounting location for any corrosion, damage, or debris. Clean the mounting surface if necessary.
8. 8

   Install new ballast module
   Position the new ballast in the mounting location, aligning the mounting holes with the bracket. Ensure any heat sink fins face downward or outward for proper cooling airflow. Start both mounting bolts by hand before tightening.
9. 9

   Torque ballast mounting bolts
   Using a torque wrench with 8mm socket, tighten the ballast mounting bolts to specification in an alternating pattern. Ensure the ballast is secure and does not move when gently pulled.
   Torque spec

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

    Reconnect ballast electrical connectors
    Connect the input power connector from the vehicle harness to the ballast first, ensuring it clicks securely. Then connect the high-voltage output connector that runs to the HID bulb. Verify both connections are fully seated with no gaps.
11. 11

    Reconnect HID bulb connector
    Carefully reconnect the electrical connector to the back of the HID bulb. Push firmly until you hear and feel a positive click. Gently tug to verify the connection is secure.
12. 12

    Reinstall headlight access cover
    Position the plastic access cover over the opening and rotate clockwise approximately 1/4 turn until it locks into place. Ensure the seal is properly seated to prevent moisture intrusion.
13. 13

    Reconnect battery negative terminal
    Reconnect the negative battery cable to the battery post. Tighten the terminal bolt to specification using a 10mm wrench and torque wrench. Do not overtighten as this can damage the battery terminal.
    ⚠Ensure battery terminal is clean and free of corrosion before reconnecting. Poor connection can cause electrical issues.
    Torque spec

    Battery Terminal Bolts6 Nm (4 lb-ft)

Reassembly

1. Ensure all electrical connections are secure and properly seated
2. Verify the ballast is firmly mounted with no movement
3. Check that access cover is properly installed and sealed
4. Confirm no tools or parts are left in the engine bay

Verification

• Turn ignition to ON position (do not start engine). HID headlights should initialize within 1-2 seconds
• Observe that the repaired headlight illuminates properly. HID bulbs take 15-30 seconds to reach full brightness
• Check for any flickering, unusual sounds, or error messages on the instrument cluster
• Compare light output and color temperature to the opposite headlight to ensure proper operation
• Turn headlights off and on several times to verify consistent startup
• If headlight still does not work, verify all connections and check that the bulb itself is not failed

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