Step-by-Step Guide to Cleaning Battery Cable Terminals

no car electrical

Everything electrical inside the car go out? Do you have lights on the dash that go dark when you try to start the car? This can be a simple problem of a bad connection at the battery terminals, in this guide will we show you how to fix this simple problem and get back on the road.

What Goes Wrong?

Heat and corrosion are an electrical connections enemy, this condition will stop the flow of electrical current leaving the car dead on the road. This problem is produced by corrosion which generally builds up on the positive battery terminal, (this is a natural side effect of current flow), or by a loose connection at the battery cables. Sometimes once the electrical power goes out it will come back again once the connection has cooled, but the problems still exists.


Do not try to crank an engine over when a person is near the battery or engine. A battery is filled with explosive gasses that may ignite when extreme heat or a spark is present, as in a bad connection. When working with a battery use protective eyewear and gloves, if battery acid is present neutralize the area using baking soda and rinsing with water before work begins. Excessive exterior battery acid is a sign the battery is bad and needs replacement. When working with a battery be sure not to touch your face, eyes or clothing with the work gloves.

Let's Get Started

1. Check Battery Cables: Grasp the battery cable and try to wiggle them loose while inspecting the terminals for corrosion. In the image below corrosion is present causing the electrical to go dead. This problem is common for the positive battery terminal and cable.

battery terminal corrosion

2. Remove Cable for Cleaning: With the ignition key, off use a 8mm or 10mm socket or wrench to loosen the cable by turning it counterclockwise.

loosen battery cable

3. Twist and lift the cable end from the battery, there might be a small spark which is normal.

battery cable removed

4. Use a wiring brush or a battery cleaning tool which you can get from Amazon for about $5.00 (US) and work it into the battery cable end to remove all corrosion. Also clean the adjacent battery terminal as well.

clean cable terminal

5. Reinstall the battery cable by pushing downward while tightening the nut. Do not over tighten the nut to avoid stripping.

tighten battery cable

6. Once tightened grasp the cable end and check it for tightness to the battery terminal then reinstall the terminal cover and you are all set.

install terminal cover

Watch the Video!

Please watch this video of the job being done to glean additional helpful information.


This guide knowledge base was created by the 2CarPros Team, and by Ken Lavacot: Automobile repair shop owner and certified master automobile technician of over 30 years. If you have question or need help please ask one of our experts we are happy to help. Please visit our 2CarPros YouTube Channel.

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