Step by step instructions on how to replace battery cables. This article pertains
to most vehicles.
Difficulty Scale: 3 of 10
Tools and Supplies Needed
- Wrench set
- Wire brush
- Shop towels
- Baking soda
- Cable replacement
Before we begin park the vehicle on a level surface, engage the parking brake,
- Once you locate the battery, use a box
end wrench to loosen the negative battery cable first. Once the bolts are loose,
twist the terminal back and forth while you pull it off. (Note: This is for a top
post battery. If your vehicle has the terminals located on the side of the battery,
once the bolt is loose, it will simply come off the battery).
- Next, use the box end wrench and loosen
the positive battery cable. Follow the same procedure from step 1 to remove it.
- Follow the negative cable to where it
mounts on the engine block. Unbolt it from that location and remove the entire cable.
- Bolt the new cable to the engine block.
- Next, follow the positive cable to the
starter solenoid and unbolt it, then reinstall the new cable. (Note: When routing
new cables, make sure they are both clear of fans, the exhaust system, or any other
moving parts. If the positive cable melts through from heat or is damaged from a
steel moving part, it will short out and can possibly cause a fire.
- After the new cables have been bolted
in place and properly routed, check the battery terminals. If there is corrosion
on them, take a wire brush and gently clean all the corrosion off. Also, use a shop
towel to dust all corrosion from the battery.
- Once the battery terminals are clean and
the new cables have been installed, reconnect the positive cable to the battery
first and tighten it. (Note: Battery cables need to be snug, not super tight.)
- Next, reinstall the negative terminal
onto the battery to complete the job.
Battery cable connections are the first place to check when major electrical
issues begin. In addition to a good battery, the terminals that connect the battery
to the vehicle can go bad, corrode, and fail. Therefore, its important to check
cable condition at regular service intervals. Check for cracking on the insulation
and corrosion on the terminals. Battery acid can cause corrosion inside the battery cables and will inhibiting electrical flow. To check for this condition look for bulges near the top of the cable, these bulges indicate corrosion expansion caused by the chemical reaction between the acid and copper wire.
- Always disconnect the negative battery cable first and last to avoid a short
- When working with a battery, acid is present so wear protective gloves,
eyewear and clothing.
- Never touch a car battery with bare hands. The battery could have residual
acid on the surface which is difficult to detect. This acid can ruin clothing
and be harmful to eyes and skin.
Article first published 2009-07-28 (Updated 2015-01-05)