🔧 Focus - Tail/Brake Bulb Replacement (Both Sides)

On your Focus, the outer taillights (left and right) are serviced from inside the trunk. You’ll remove each taillight housing, swap the bulb in the twist-lock socket, then reinstall and test all rear light functions.

Difficulty Level: Beginner | Estimated Time: 0.5-1.0 hours

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⚠️ Safety & Precautions

• ⚠️ Turn the light switch OFF and remove the key before starting.
• ⚠️ Let bulbs cool first; they can be hot.
• ⚠️ Don’t touch new glass bulbs with bare fingers; oil can shorten bulb life.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 1/4" ratchet
• 6" socket extension
• Plastic trim tool
• Flashlight
• Nitrile gloves
• Safety glasses

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• Rear tail/brake bulb (dual-filament, 3157) - Qty: 2

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📋 Before You Begin

• Park on level ground and open the trunk.
• Make sure the headlight switch is OFF and no lights are on.
• Lay a towel on the bumper edge.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Open the trunk and access the taillight fasteners

• Use a flashlight to locate the access area behind each taillight inside the trunk.
• If your trunk trim has a small cover/door, pop it open using a plastic trim tool.

Step 2: Remove the taillight nuts (one side at a time)

• Use a 10mm socket, 6" socket extension, and 1/4" ratchet to remove the taillight retaining nuts.
• Set the nuts aside where they won’t fall into the trunk trim.

Step 3: Remove the taillight housing

• Grip the taillight from the outside and pull it straight rearward (toward you).
• If it feels stuck, wiggle gently while pulling straight back. Avoid prying on the painted body.
• It’s held by alignment pins—straight back is key.

Step 4: Remove the bulb socket

• Locate the tail/brake bulb socket on the back of the taillight.
• Twist the socket counterclockwise by hand to unlock it, then pull it out.
• (A “twist-lock socket” is a plastic holder that locks in place by turning.)

Step 5: Replace the bulb

• Put on nitrile gloves.
• Pull the old 3157 bulb straight out of the socket.
• Push the new 3157 bulb straight into the socket until fully seated.

Step 6: Reinstall the socket and taillight

• Insert the socket back into the taillight and twist clockwise to lock.
• Align the taillight pins with the body holes and press the housing straight into place.
• Install the nuts using the 10mm socket, extension, and ratchet.
• Torque to 3 Nm (27 in-lb)

Step 7: Repeat on the other side

• Repeat Steps 1–6 for the other taillight.

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✅ After Repair

• Turn the lights on and confirm: parking lights (dim) and brake lights (bright).
• Verify turn signals and hazard lights still work normally.
• If a new bulb doesn’t light, remove it and rotate/reseat it, then re-test.

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💰 DIY vs Shop Cost

Shop Cost: $80-$180 (parts + labor)

DIY Cost: $10-$30 (parts only)

You Save: $70-$150 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 0.5-1.0 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.