How to Replace Battery Cables

If you drive a vehicle with an internal combustion engine, you can think of the battery like your vehicle’s beating heart. The battery cables act like arteries running a current to the alternator, which powers electronic systems such as the ignition system, the ECM (Electronic Control Module) and the lighting system.

Bad Battery Cable Symptoms

Just like in other areas of your vehicle, the components of your battery system will wear out and fail over time. Symptoms of worn or frayed battery cables are like that of a dying battery:

• Dimming or flickering of interior lights or headlights
• Engine hesitation when starting
• Clicking noises

If you notice a buildup of flaky white or blue crust around the top or sides of your battery, that’s corrosion. It’s a common problem caused by small amounts of escaping hydrogen gas or leaking electrolytes on the top of your battery or the battery cable terminals. Corrosion can develop on older batteries that were overcharged, undercharged or exposed to certain environmental factors.

The NAPA Network can show you how to replace battery cables in your car, as well as replace your battery, your battery terminals, your battery posts and—depending on the extent of the damage—your battery tray and battery hold-down. If you determine your battery has good voltage by using a multi-meter and doesn’t need replacing, then it’s time to check your battery cables.

Start at the cable terminals attached to the battery posts. Inspect both the positive and negative cables for fraying, knicks and splits. If you see anything that doesn’t look right, it’s time to replace the cables.

Replacing Battery Cables

Just like any good at-home automotive repair, you should start with all your tools ready to go, as well as safety equipment such as eye protection and gloves. Replacing battery cables is straightforward, and you’ll need the following:

• A Screwdriver
• A Socket Wrench
• A Wrench
• A Ratchet

Step 1 – Using the screwdriver or socket wrench, gently disconnect the battery terminals from the battery posts—starting with the negative cable—then disconnect the positive to avoid shorting and potential danger. Trace the path of the negative cable to the chassis, then trace the positive cable to the fuse box. Make sure to take a picture or otherwise note the course so you can route the new cables correctly.

Step 2 – Use the ratchet to loosen the negative ground nut, then remove the nut that holds the positive cable to the fuse block. Inspect these for corrosion and damage and replace them if the metal is soft or the threading is deteriorated. Inspect the terminal posts on top of the battery and use a battery terminal cleaner to remove any corrosion.

Step 3 – Install the new cables starting with the negative. Reattach the negative ground nut to the chassis and the nut that holds the positive cable to the fuse block. Make sure the nuts are tight and snug.

Step 4 – Route the cables the way you originally found them and connect the terminal ends to the clean battery posts starting with the positive cable, then the negative cable.

Step 5 – Start your vehicle and ensure the electrical systems work properly.

Removing corrosion, cleaning your battery terminals and replacing worn battery cables is a part of routine vehicle battery maintenance that most at-home mechanics can do. However, this job involves the electrical system of your vehicle, so if you don’t feel comfortable doing the replacement yourself or can’t find the time, we are here to help. Just find a friendly local NAPA Auto Care location near you, and one of our ASE-certified technicians will replace the battery cables in your vehicle for you. We can even help you with an Instant Repair Estimate to help you budget for your repairs and get you back on the road in no time!

Photo courtesy of Pexels.