What to Do If Your Car Battery Light Comes On

Are you feeling confused and frustrated after your car battery light unexpectedly came on? We understand! To help relieve the worry and confusion, we have all the information you need about what to do when this happens. Keep reading for simple steps to take if you ever find yourself in this situation.

In this article, we’ll cover everything you need to know when the battery light comes on, such as what I causing it and how to troubleshoot it. So make sure to keep reading!

Let’s get started.

How Does the Battery Work?

The 12-volt rechargeable battery is the heart of your car’s electrical system, providing power to all of the vehicle’s accessories and components. When you turn on your vehicle, the battery supplies power to the starter motor, starting the engine.

Once the engine is running, the alternator takes over and provides power to your vehicle’s electrical system. The alternator, powered by the engine, then charges the battery, ensuring enough power is available for the next time you turn on your car.

The serpentine belt, also called the drive belt, drives the alternator via the engine. The serpentine belt must be in good condition and tight for the alternator to work properly and maintain smooth operation.

It also operates the air conditioning, power steering pump, and in some vehicles, the water pump.

By understanding how the battery works, you are one step closer to determining what issue you’re dealing with and what to do if the battery light comes on.

What Does the Battery Light Mean?

The battery light on a car’s dashboard indicates a problem with the car’s charging system. It is typically a sign that the battery is not being charged properly, which can be caused by a variety of issues such as a faulty alternator or a malfunctioning battery.

If the brake light comes on for a few seconds at start-up, there is no reason to worry. It’s completely normal and simply illuminates that the dashboard light is working.

However, you should pay attention if the light stays on or comes on while driving. If it does, the car is telling you there’s a problem with the charging system and that your battery may not charge. By continuing driving, your battery may eventually drain, leaving you stranded.

On the other hand, a common scenario is when the battery light comes on and off, for example, when braking, accelerating, turning, or just at any time.

This is usually a sign of poor connection between the battery and alternator and is often caused by a loose or corroded battery cable or damaged terminals.

Here are the most common causes why a battery light might come on:

  • A Loose or corroded battery cables
  • A problem with the alternator
  • A problem with the voltage regulator
  • Damaged terminals
  • Damage inside the battery
  • Faulty wiring

What to Do If Your Battery Light Comes On

Now that you know what the battery light means and why it could be illuminated, let’s see what to do if your battery light comes on.

First, if your battery light is on and the car is running, turn off all electrical accessories such as the radio, heated seats, and air conditioning, unplug your phone and turn off the headlights if it’s daytime. This will help reduce the load on the battery and save every little charge that is left.

If you notice a loss of power steering or overheating, pull over and turn off the car immediately. These are signs that you may have a broken serpentine belt.

How to Troubleshoot Your Battery Light

If your dashboard battery light is on, it means your car’s charging system is not working properly. It could mean it’s time to replace the battery. But the light could also be caused by a minor problem, like a loose battery cable, which is a quick fix!

Here are some troubleshooting tips to help you figure out what’s causing your battery light to come on.

1. Visually Inspect the Battery 

Let’s start with the simplest thing, a visual inspection. Here’s how you do it:

Step 1: Turn off the car. 

Make sure your vehicle is turned off and parked at a safe location. If you had to stop in a bad place, use your warning triangle for your safety. If possible, move your car to a safer location that’s well away from traffic. Pop up your hood and make sure to use safety gear if available.

Step 2: Locate the battery. 

Once you’ve popped your hood open, locate the battery. It will usually be in one of the corners on either side of the engine bay, near the front bumper or the windshield. The battery is a rectangular box with two cables attached to it. If it is underneath a plastic cover, remove the cover if necessary.

Note: In some vehicles, the battery is located in the trunk. Suppose you aren’t able to find the battery. Then check your owner’s manual.

With your safety gloves on, remove any covers or plastic that might cover the terminals on top of your battery.

Step 3: Look for corrosion.

While troubleshooting your battery light, the first thing you could do is check for corrosion. Battery corrosion is common, especially if you live in a place where it is year-warm weather.

The corrosion can create problems and affect the conduction of electricity between your battery and the rest of the car. Check for a white, green, blue, or grayish substance or powdery buildup around the terminals. If there is, it means you have corrosion.

Step 4: Clean the battery terminals. 

Please do not touch the corrosion with bare hands; it can cause skin irritation! Use protection gloves, like dish gloves. Remove the plastic covers, and disconnect the cables from the battery. You can use a cable tie to secure it so it doesn’t get in the way.

Use 100-grit sandpaper or emery cloth to clean the terminals carefully. If you don’t have sandpaper or emery cloth, here is a guide on how to clean battery terminals with stuff you might have at home by firestonecompleteautocare.com

  • When disconnecting your battery, always remove the negative battery cable first to prevent electrical shorts.
  • When reconnecting the battery cables to the battery, reconnect the positive cable first.

Look for loose battery cables. Another common reason why your car battery light comes on is a poor connection between the battery and the cables attached to it. If you notice the clamps are loose, use a small wrench to tighten them.

2. Test the Alternator

Unfortunately, there is only one way to know for sure if your alternator is bad, which is to have it tested.

Start by conducting a voltmeter test on the battery. An alternator should test between 12 and 13.5 volts. This requires a voltmeter or multimeter and some basic knowledge. Check out this guide on how to test an alternator from wikiHow.

There are two quick and easy tests you could try if you are not close to an auto parts store or have a voltmeter in your car or at home. These tests are not as reliable as conducting a voltmeter test but could give you the first hint if the alternator is going bad.

Headlight test

To perform this test, you will need a friend to help you out. Start the car and turn on your headlights. With the vehicle in park, ask your friend to observe the headlights as you press the accelerator. If there is no change in the headlight brightness, it means your alternator is fine. However, the alternator is likely bad if the headlights dim, flicker, or get brighter as the accelerator is pressed down.

Battery test

A battery test is easy to perform yourself and will require a wrench and protection gloves. First, pop your hood open and start your car. With the engine running, remove the negative cable from the battery. To keep the engine running on its own, the alternator needs to generate enough electricity. If it doesn’t, and the alternator is bad, your car will stall or die.

If the alternator is making rumbling or squeaking sounds is another indicator that it might be bad or dying.

3. Check the Serpentine Belt 

The serpentine belt is a long, flat belt that goes around all of the pulleys on the engine except for the timing belt. If your battery light comes on, and you are having issues with loss of power steering or overheating, it’s likely caused by the serpentine belt.

Turn off your car immediately, open your hood and look for any cracks or breakages in the belt – or a complete loss of the belt.

4. Check Your Fuses

A fuse might not cause direct issues with battery charging problems. However, it could cause your battery light to come on if the fuse somewhere links the battery and the alternator. So it might be worth looking for any blown fuses and replacing them.

5. Start Your Car

If the light turns off, the issue is likely fixed. If the battery light remains after troubleshooting, you might want to consult a professional mechanic or take your car to an auto shop to have it checked.


How Long Can You Drive With the Battery Light On?

If your battery light comes on, you should be able to drive on however much charge there is left. If you turn off all electrical accessories such as radio or air conditioning, you might be able to drive for a max of 15 to 30 minutes.

Is It Safe to Drive Your Car With the Battery Light On?

It is generally safe to drive with the battery light on. However, this means there is an issue with the charging of your battery, and your battery will eventually drain. If you notice a loss of power steering or engine overheating, you should immediately pull over.


While there are many reasons your battery light might come on, most can be fixed relatively easily. The battery light means there is a battery charging issue, and most times, you can troubleshoot your battery light yourself.

I hope you found this article helpful and that you managed to fix your issue!

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Rickard Cefalk

Rickard is the owner of Caraspect.com and a dedicated and avid do-it-yourselfer who has always enjoyed working on his own vehicles since childhood. He now devotes his time to sharing his expert knowledge of car maintenance and other car-related information through his website.

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