Today vehicles are all equipped with a 12-volt battery that recharges as you drive. The battery powers the electrical components such as the lights (headlights and interior), radio, ignition system, and much more. Without the battery, your car will not run.

It used to be that the only way you knew that battery was about to fail was to physically measure the voltage coming from the battery, or sometimes you might notice the headlights would begin to flicker.

Today, our vehicles are much safer. One such way being the dashboard light that indicates there is an issue with your battery. Now, the battery issue can be identifyed and corrected before you end up with a dead battery. This can prevent becoming stranded somewhere.

What does the Battery Light Mean When On?

There are a series of different problems the battery light being on might indicate. The first step to correcting the issue is identifying what’s going on. Then you can decide if you can replace the parts yourself or if you need to find a reputable service center. Common issues that light up the battery indicator light are as follows.

Battery Terminal Corrosion

If the terminals on your battery have become corroded, you might first notice that the car turns over more slowly than you’re used to. Sometimes the corrosion will block the flow of electricity, and the battery light will light up on the dash.

To determine if the terminals are corroded, check for crusty white powder built up where the battery cables attach. You can clean this off with a solution of baking soda. Just mix the baking soda (1 tbs) with 3/4-1 cup of water. Remove the battery cables before you begin and scrub it with an old toothbrush.

Loose Cable to the Battery

Sometimes the problem is even simpler than corroded terminals. Sometimes it’s merely that the battery cables are not securely attached to the battery. Usually, this happens after a rough ride or after installing a battery.

To check to see if this is an issue, ensure the cable is situated all the way into the post and that the nut has been tightened to the point that it stops turning. If you notice it’s corroded too, it’s a good time to give it a bit of a clean too.

Low Battery

Once the battery is older than three years, if you are getting a battery indicator or symptoms of a weak battery, it could merely be that the battery is exhausted.

A new battery has a warranty (48, 72, 96 months). Batteries frequently die before that period. Sometimes it’s due to factors like where you live (warmer areas like Florida) that result in premature exhaustion of the battery. Sometimes the battery is to blame. A warranty may cover a free replacement battery or a pro-rated credit towards a new one if the battery dies before it’s warranty period.

In order to test to see if your battery has failed, you will need a multimeter. If you have one at home, you are looking for a voltage reading between 12.4-12.7. Anything reading less than 12.2 volts indicates a replacement is needed. For those without a multimeter, many auto parts stores will test your battery for free.

Alternator is Bad

Alternators keep the battery charged up as you drive the vehicle. They last for 80,000-120,000 miles usually (5-7 years). If you are seeing a battery light on your dash and your car is approaching that point, you may have a bad alternator. A bad alternator isn’t going to keep the battery charged.

Once your vehicle starts experiencing inconsistent charge, it will detect the issue and light up the dashboard light. The alternator will ultimately die, and then the battery will as well shortly after. The alternator will need to be either replaced or rebuilt.


While this is not an exhaustive list on what may be the cause of the battery light being on, it is the more likely suspects. While some of these are easy DIY problems (cleaning the posts or tightening the cables), some will have you wanting to reach out to a trusted service center. Consider Auto Alternative Service & Sales the next time you need to have your vehicle checked out in Nicholasville, KY. Contact us to set up an appointment.