🔧 4Runner - Headlight Bulb Replacement (Both Sides)

On your 4Runner, the headlight bulbs sit behind the headlight housings and can be replaced from the engine bay. The key is accessing the rear dust cover, swapping the bulb without touching the glass, and re-sealing everything so moisture can’t get in.

Difficulty Level: Intermediate | Estimated Time: 0.8-1.5 hours

Assumption: your Limited uses HID D4S low beams; halogen steps are included too.

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⚠️ Safety & Precautions

• ⚠️ Turn headlights OFF and let them cool 10+ minutes before touching anything.
• ⚠️ HID systems create high voltage at the igniter; disconnect the battery before opening the HID bulb area.
• ⚠️ Do not touch the bulb glass with bare fingers; oil can shorten bulb life.
• ⚠️ Make sure the rear dust cover seals fully to prevent condensation inside the headlight.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" ratchet
• 6" socket extension
• Trim clip remover
• Small flathead screwdriver
• Nitrile gloves
• Safety glasses
• Flashlight

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Low beam HID bulb (D4S) - Qty: 2
• Low beam halogen bulb (H11) - Qty: 2
• Dielectric grease (small packet) - Qty: 1

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the hood and support it securely.
• Disconnect the negative battery terminal using a 10mm socket and 1/4" ratchet.
• Lay tools on a towel to avoid scratches.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Create working room (each side)

• Use a flashlight to look behind each headlight and locate the round rear dust cover.
• If your hands don’t fit well, remove a few nearby plastic clips using a trim clip remover to move the intake snorkel/covering slightly (do not force).

Step 2: Remove the rear dust cover

• Put on nitrile gloves and safety glasses.
• Twist the dust cover counterclockwise by hand and pull it off.
• Set the cover someplace clean so dirt won’t fall inside the housing.

Step 3 (HID D4S): Remove the igniter and bulb

• Igniter definition: the round module attached to the bulb that generates the high-voltage spark for HID.
• Release the electrical connector by pressing the tab (help gently with a small flathead screwdriver if needed), then pull the connector straight off.
• Twist the igniter/module counterclockwise and remove it from the back of the bulb.
• Remove the bulb retaining ring (turn counterclockwise), then pull the D4S bulb straight out.
• Do not rotate the bulb while pulling it out.

Step 4 (Halogen H11): Remove the bulb

• Press the connector tab and pull the connector off the bulb.
• Twist the H11 bulb counterclockwise and pull it straight out.

Step 5: Install the new bulb (same for both sides)

• Without touching the glass, insert the new bulb straight into the socket (match the tabs/shape so it seats fully).
• Lock it in place:
  • HID D4S: install and tighten the retaining ring (snug by hand), then reinstall the igniter and twist clockwise to lock.
  • Halogen H11: twist clockwise to lock.
• Apply a tiny amount of dielectric grease to the connector seal (not the bulb) and reconnect the electrical connector until it clicks.

Step 6: Reinstall the dust cover and any clips

• Reinstall the dust cover and twist clockwise until fully seated.
• Reinstall any intake/trim clips you moved using the trim clip remover (to align) and hand pressure to snap them in.

Step 7: Reconnect the battery

• Reconnect the negative battery terminal using a 10mm socket, 1/4" ratchet, and 6" socket extension.
• Torque to 5 Nm (44 in-lbs)

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✅ After Repair

• Turn the headlights on and confirm both low beams work.
• Check high beams and turn signals to make sure you didn’t bump another connector.
• At night, verify the beams look even left-to-right; if one looks “off,” the bulb may not be seated correctly.
• Look for moisture inside the lens over the next day—if you see fogging, recheck the dust cover seal.

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💰 DIY vs Shop Cost

Shop Cost: $160-$350 (parts + labor)

DIY Cost: $60-$220 (parts only, depends on HID vs halogen)

You Save: $100-$200 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.8-1.2 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.