🔧 Regal - 12V Battery Replacement

Replacing the 12V battery restores reliable starting and prevents random electrical issues. On your Regal, the battery is in the trunk, so access is easy, but you must disconnect and reconnect it in the correct order.

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

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⚠️ Safety & Precautions

• ⚠️ Keep metal tools off both terminals at once; it can short and spark.
• ⚠️ Turn ignition OFF, remove key/fob from the car, and wait 2-3 minutes before disconnecting.
• ⚠️ Wear gloves and safety glasses; batteries can leak acid and vent gas.
• ⚠️ Disconnect the negative (−) cable first, reconnect it last.
• ⚠️ Do not smoke or make flames/sparks near the open trunk while working.

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🔧 Required Tools

You'll need the following tools for this repair:

• 10mm socket
• 13mm socket
• 3/8" ratchet
• 6" extension for 3/8" ratchet
• Trim clip remover
• Flathead screwdriver
• Torque wrench (10-50 Nm range)
• Battery terminal puller (specialty)
• Battery carry strap
• Nitrile gloves
• Safety glasses
• Memory saver (12V OBD-II) (specialty)

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• 12V battery (AGM, H6/Group 48 size) - Qty: 1
• Battery terminal corrosion protection spray - Qty: 1
• Battery terminal felt washers - Qty: 2

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📋 Before You Begin

• Park on level ground, shift to Park, and set the parking brake.
• Open the trunk and keep it open while you work.
• If you have a memory saver (12V OBD-II), plug it into the OBD port before disconnecting the battery to help keep radio presets and some settings.
• Remove trunk floor panels and the right-side trunk trim panel as needed to expose the battery.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Access the battery in the trunk

• Lift the trunk floor panel by hand and remove any storage tray.
• Use a trim clip remover to pop out the plastic push clips holding the right-side trunk liner.
• If a clip is stubborn, gently pry with a flathead screwdriver.

Step 2: Disconnect the negative (−) battery cable

• Use a 10mm socket with a 3/8" ratchet to loosen the negative terminal clamp nut.
• Twist and lift the clamp off the negative post.
• If it’s stuck, use a battery terminal puller (specialty); it removes a tight clamp without prying.
• Tip: Tuck the cable aside so it can’t spring back.

Step 3: Disconnect the positive (+) battery cable

• Flip open the positive terminal cover (if equipped) by hand.
• Use a 10mm socket to loosen the positive terminal clamp nut.
• Remove the clamp and set it aside so it cannot touch metal.

Step 4: Remove the battery hold-down

• Locate the battery hold-down bracket at the base of the battery.
• Use a 13mm socket with a 6" extension for 3/8" ratchet to remove the hold-down bolt(s).
• Set the bracket and bolt(s) somewhere safe.

Step 5: Remove the old battery

• Attach a battery carry strap and lift the battery straight up and out.
• Keep it level; batteries are heavy and can leak if tipped.

Step 6: Prep the terminals and tray

• Check the battery tray area for corrosion or moisture and wipe it clean.
• Install battery terminal felt washers on the posts (one per post) if you’re using them.
• Lightly apply battery terminal corrosion protection spray after the cables are installed (not before).

Step 7: Install the new battery

• Place the new AGM H6/Group 48 battery into the tray in the same orientation as the old one.
• Reinstall the hold-down bracket and tighten using a 13mm socket.
• Torque to 20 Nm (15 ft-lbs).

Step 8: Reconnect the positive (+) cable first

• Install the positive clamp fully down on the positive post.
• Tighten using a 10mm socket.
• Torque to 7 Nm (62 in-lbs).
• Close the positive terminal cover.

Step 9: Reconnect the negative (−) cable last

• Install the negative clamp fully down on the negative post.
• Tighten using a 10mm socket.
• Torque to 7 Nm (62 in-lbs).
• Lightly spray the terminals with battery terminal corrosion protection spray.

Step 10: Reinstall trunk trim

• Reposition the trunk liner and press clips back in by hand.
• Reinstall the trunk floor and any trays you removed.

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✅ After Repair

• Start the engine and confirm it cranks strongly.
• Check that headlights, power windows, and locks work normally.
• If you did not use a memory saver, reset the clock and radio presets.
• Drive normally for 15-20 minutes so the charging system can stabilize.
• If a warning light appears, it often clears after a few drive cycles; scan if it remains.

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💰 DIY vs Shop Cost

Shop Cost: $250-$450 (parts + labor)

DIY Cost: $170-$320 (parts only)

You Save: $80-$130 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.