🔧 Fusion - Battery Replacement

On your Fusion, the 12V battery powers starting and all electronics. Replacing it is straightforward, but you must disconnect/reconnect in the right order and then reset the Battery Monitoring System (BMS) so charging works correctly.

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

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⚠️ Safety & Precautions

• ⚠️ Turn ignition OFF and remove the key before starting.
• ⚠️ Disconnect the negative (–) cable first, reconnect it last.
• ⚠️ Do not let a tool bridge the battery positive (+) to metal.
• ⚠️ Batteries can vent explosive gas; no sparks/flames nearby.
• ⚠️ Wear eye protection and gloves; battery acid is corrosive.
• 🔋 Battery disconnect is required for this job.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• 10mm socket
• 13mm socket
• 1/4" ratchet
• 3/8" ratchet
• 6" extension
• Torque wrench (inch-pound)
• Torque wrench (foot-pound)
• Battery terminal puller (specialty)
• Battery brush terminal cleaner
• Fender cover
• Shop rags

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V battery (match your current group size and CCA) - Qty: 1
• Battery terminal anti-corrosion pads - Qty: 2
• Battery terminal protectant spray - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, shift to neutral, and set the parking brake.
• Open the hood and install a fender cover to protect paint.
• If you want to avoid losing radio presets, use a memory saver (optional). If you don’t have one, it’s okay—your Fusion will relearn, but the clock/presets may reset.
• Locate the battery at the front of the engine bay on the driver side.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the battery hold-down

• Use a 10mm socket and 1/4" ratchet to remove any covers or small retainers that block access (if equipped).

Step 2: Disconnect the negative (–) battery cable

• Use a 10mm socket and 1/4" ratchet to loosen the negative terminal clamp bolt.
• Twist and lift the clamp straight up off the battery post. If it’s stuck, use a battery terminal puller (specialty) (a small tool that lifts the clamp without prying).
• Tuck the negative cable to the side so it cannot spring back onto the post.
• When reinstalling later: Torque to 7 Nm (62 in-lbs)

Step 3: Disconnect the positive (+) battery cable

• Use a 10mm socket and 1/4" ratchet to loosen the positive terminal clamp bolt.
• Lift the clamp off the post and position it aside so it can’t touch the battery.
• When reinstalling later: Torque to 7 Nm (62 in-lbs)

Step 4: Remove the battery hold-down clamp

• Use a 13mm socket, 3/8" ratchet, and 6" extension to remove the battery hold-down bolt at the base of the battery.
• Remove the hold-down clamp and set it aside.
• When reinstalling later: Torque to 10 Nm (89 in-lbs)

Step 5: Lift out the old battery

• Use gloves and lift the battery straight up and out.
• Batteries are heavy; lift with legs.

Step 6: Clean and prep the connections

• Use a shop rag to wipe the battery tray clean.
• Use a battery brush terminal cleaner to clean the inside of both cable clamps until shiny metal is visible.
• Install battery terminal anti-corrosion pads onto the new battery posts.

Step 7: Install the new battery and secure it

• Set the new battery into the tray in the same orientation as the old one.
• Reinstall the hold-down clamp and bolt using a 13mm socket and 3/8" ratchet.
• Final tighten with a torque wrench (inch-pound): Torque to 10 Nm (89 in-lbs)

Step 8: Reconnect the battery cables (positive first)

• Install the positive (+) clamp first and snug it using a 10mm socket and 1/4" ratchet.
• Final tighten with a torque wrench (inch-pound): Torque to 7 Nm (62 in-lbs)
• Install the negative (–) clamp last and tighten using a 10mm socket.
• Final tighten: Torque to 7 Nm (62 in-lbs)
• Apply battery terminal protectant spray to reduce corrosion.

Step 9: Reset the Battery Monitoring System (BMS)

• This tells your Fusion the battery is new so charging strategy is correct.
• Method A (no scan tool): Turn ignition ON (engine OFF). Within 10 seconds, flash the high beams 5 times, then press and release the brake pedal 3 times.
• If successful, the battery warning indicator will flash (or you may notice a brief confirmation behavior). If nothing happens, repeat the sequence a bit quicker.
• Method B (scan tool): Use a capable scan tool to run the BMS reset / Battery replacement function.

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✅ After Repair

• Start the engine and confirm normal cranking and no warning lights.
• Check that both terminals are fully seated and cannot rotate by hand.
• Set the clock and re-save radio presets if they were lost.
• Take a 10-15 minute drive so charging and idle can relearn.

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💰 DIY vs Shop Cost

Shop Cost: $220-$420 (parts + labor)

DIY Cost: $140-$280 (parts only)

You Save: $80-$200 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.