Battery Light on Dashboard [9 Reasons Why It’s On]

You should always pay attention to the lights on your dashboard when driving, as they may be alerting you of a severe issue with your car. This is especially true with the car battery warning light. What causes the battery light on the dashboard to come on, and what should be done about it?

Nine causes why the battery light on the vehicle’s dashboard turns on are the following:

  1. Broken Auxiliary Drive (Serpentine) Belt
  2. Bad Alternator
  3. Broken Alternator to Dash Cluster Wire
  4. Faulty Dash Cluster
  5. Bad Battery
  6. Corroded Battery Terminals
  7. Broken or Corroded Engine Earth Strap
  8. Worn Alternator Pulley
  9. Loose or Faulty Battery Cable

The steps for fixing the battery light on the dashboard are the following:

  1. Inspect the Battery
  2. Examine the Alternator
  3. Observe the Fuse
  4. Test the Battery

Read on to learn more about the battery light on the dashboard, its causes, and how to fix it.

Battery Light on Dashboard [Causes and How to Fix]

battery light on dashboard

When the car battery light turns on while you’re driving, it is most commonly caused by a broken serpentine or auxiliary drive belt. Other probable causes include faulty wirings or a broken alternator. The light comes on due to either a defective dash cluster or a faulty car battery on rare occasions.

There are several causes why the battery light on the vehicle’s dashboard turns on. These include the following:

  1. Broken Auxiliary Drive or Serpentine Belt
  2. Bad Alternator
  3. Broken Alternator to Dash Cluster Wire
  4. Faulty Dash Cluster
  5. Bad Battery
  6. Corroded Battery Terminals
  7. Broken or Corroded Engine Earth Strap
  8. Worn Alternator Pulley
  9. Loose or Faulty Battery Cable

Let’s discuss each of these causes:

1. Broken Auxiliary Drive or Serpentine Belt

Unable to Spin the Alternator

A broken auxiliary drive belt is the most common reason a battery light comes on while driving. When the serpentine belt breaks, it will be unable to spin the alternator, preventing it from generating the electricity needed to charge the battery.

The battery light then turns on to warn you that there is a problem. Other symptoms associated with a broken serpentine belt include loss of air conditioning and power steering.

Inspect the Engine

To diagnose a faulty auxiliary drive belt, conduct a visual examination on the engine to determine if the belt has snapped.

As long as you haven’t driven your car for a lengthy period without a belt, you may be able to get away with just having it replaced and driving your car normally as usual.

Remove All Traces of Debris from the Old Serpentine Belt

Be certain to remove all traces of debris leftover from the old serpentine belt, which may have gotten stuck in various parts of the engine bay, to avoid problems if it gets caught in cooling fans or pulleys.

2. Bad Alternator

Prevents the Alternator from Charging

An alternator is an intricate unit consisting of numerous internal components. Should any of these components ever malfunction, it will prevent the alternator from charging at the current rate required by your car.

Use a Multimeter to Diagnose

You can use a multimeter to diagnose the condition of the alternator easily. The voltage must be between 13.6 and 14.6 volts. If it is less than 12 volts, the battery light will be activated, and the alternator will likely have to be replaced. 

Alternatively, the voltage regulator, which safely limits the output to 14.5 volts, may also cause problems if it isn’t functioning normally.

3. Broken Alternator to Dash Cluster Wire

The wire feeding the dash cluster is usually a small 15-amp cable, making it more prone to wear and corrosion. Often, this wire is connected to the alternator through a standard block connector. It runs either directly to the dash cluster or through an Engine Control Unit (ECU). 

Allow a Mechanic to Check the Battery and Alternator

The easiest way to determine the problem is by eliminating other causes. Allow a mechanic to check both the battery and the alternator. This is to ensure that they are both functioning properly. If no faults are found in any of these, you will next examine the wire. 

Inspect the Block Connector

Inspect the block connector fitted on the back of the alternator. Make sure that a good connection can be visibly seen.

Then, thoroughly examine the actual wire for signs of breakage or corrosion in the cable. If you find rust, repair and run your car to ensure that the battery light turns off after startup.

4. Faulty Dash Cluster

A faulty dash cluster is one of the less common battery light causes. But a malfunctioning dash cluster often occurs enough to warrant due attention.

Comes with Other Problems

A faulty dash cluster typically comes with other problems. These include inaccurate odometer readings or causing other illumination lights to turn on or off when they shouldn’t be.

Take the Car to a Specialist

To find out whether or not your dash cluster has malfunctioned, you will usually need to take it to a specialist to be bench tested.

5. Bad Battery

A faulty battery is another common problem that may cause your battery light to turn on while you’re driving. If a cell in the battery shorts out, it would be unable to accept the electrical feed from the alternator.

Car Is Slow to Start

This prevents it from getting charged. Another symptom is if your car is slow to start, particularly on colder mornings.

A 12-volt Battery Usually Lasts up to Five Years

Usually, a 12-volt battery has a lifespan of three to five years. Although some manufacturers claim a longer battery life, batteries are not typically expected to last beyond that lifespan.

Battery’s Cells or Plates Deteriorate Due to Age

A conventional battery usually has a lead dioxide plate. It also has a lead plate submerged in a sulfuric acid electrolyte solution in each of the six cells. The cells or plates will break as the battery ages while the electrolyte solution leaks. In this case, you will need to replace the battery.

Have the Car’s Battery Tested

A multimeter will not be enough to detect a shorted cell inside your battery. To diagnose a faulty battery, you will have to take it to the garage to get tested.

6. Corroded Battery Terminals

Avoid Covering the Terminals with Poorly-conducting Substances

The positive and negative terminals of a car battery are used for channeling electricity. It is essential to avoid covering them with poorly-conducting substances.

Corroded Terminals Become Poor Conductors of Electricity

When electrical components get corroded, they become poor conductors. This often causes bad connections in an otherwise functioning system.

Corrosion is a by-product of a reaction that usually occurs and accelerates due to persistent heat. Usually associated with hot climates, it is an acidic white, blue, or green substance that can eat away your car’s paint. This causes your skin to get irritated, so be careful.

On the other hand, typical rust has a reddish tint and can also affect the conductivity of electrical components.

Clean the Terminals

If you find signs of corrosion on the terminals of your battery, wear the appropriate safety gear before you clean the terminals. With a stiff-bristled brush, apply an alkaline solution of one tablespoon of baking soda dissolved in one cup of water to neutralize the acid present in the corrosion.

7. Broken or Corroded Engine Earth Strap

A broken or corroded earth strap is not a very common problem. But it still should not be overlooked. Just like with loose or corroded battery connections, it can also cause a host of unusual faults in your car.

Easy to Detect

However, it is rather easy to detect. You will find it between the body and the engine. If not, it is between the negative battery terminal and the body.

Inspect the Car’s Earthing Straps for Breakage or Tear

Conduct a visual inspection of the earthing straps of your car and look for any breakage or tearing. It is important that you also check for corrosion build-up at either end of the straps. This may also cause a poor earth connection.

Use an Emery Paper for Cleaning

To ensure a good connection, remove the fixing bolts and use a fine piece of emery paper to clean up the contact points. Refit the strap afterward and torque the fixing bolts fully.

Again, why is the battery light on the dashboard? If the battery light on the dashboard is on, then the car has a battery charging issue. Specifically, the battery does not supply enough power for the car to run properly.

8. Worn Alternator Pulley

A worn-out alternator pulley is not common on most cars, but it is much more common on German car models. This is because their alternators have a specially-designed pulley made to spin only one way.

Prevents the Alternator from Getting Damaged

Its design prevents the alternator from getting damaged. But it can cause serious problems should anything go wrong.

Manually Diagnose the Problem

Remove the auxiliary drive belt and turn the alternator pulley hand manually to diagnose this problem. This should enable it to spin in the direction of rotation freely. If it doesn’t, then you will need to replace the pulley. You can do this without having to replace the entire alternator assembly.

9. Loose or Faulty Battery Cable

Battery Cable Delivers Power from the Battery to the Car

While they may be small, battery cables perform an essential function. It delivers power from the battery to the car itself. If the car does not receive the power, you most likely can’t use it.

Battery cables need to fit comfortably around the battery terminals to establish a good connection. You shouldn’t be able to rotate the end of the cable by hand around the battery post.

Use Pliers or a Wrench to Tighten the Cable

If there doesn’t appear to be a good connection, use pliers or a wrench to tighten the cable. That way, it will fit securely. Be careful not to overdo it, as some battery bolts tend to strip out if they are overtightened.

How to Fix Battery Light on Dashboard

battery indicator light on dashboard

You can follow these suggested instructions for fixing the battery light on your car’s dashboard:

  1. Inspect the Battery
  2. Examine the Alternator
  3. Observe the Fuse
  4. Test the Battery

Let’s briefly discuss each one of them:

1. Inspect the Battery

Check the battery for any sign of damage or corrosion on the terminal of the battery. If you detect any corrosion, find a way to clean it off. Then, check to ensure that the clamps on the battery’s terminal are properly secure.

2. Examine the Alternator

Observe your car’s alternator to determine any missing components or loose connections. Find replacements for lost parts and properly tighten any loose connections you discover.

3. Observe the Fuse

The fuses won’t necessarily cause any direct problems with the battery charging operation of your car. But there might be a blown a fuse somewhere which links the battery with the alternator.

This issue can cause the battery light in your car to turn on. You may also want to check if you have a faulty auxiliary drive belt and have it replaced if necessary.

4. Test the Battery

After you have observed the battery and the other components of your car, the next step is to test the battery. Start the engine to find out if the light will again turn on. If it does, there is likely an issue with the alternator. If it doesn’t, then the problem has been fixed.

Frequently Asked Questions – What Does the Battery Light on the Dashboard Mean?

battery indicator on dashboard

Here are some frequently asked questions that will help you understand why the battery light on your car’s dashboard turns on:

Why Does the Battery Light Come On?

The battery warning light should turn on briefly whenever you start your car. Then, it turns back off a few seconds after. It serves as a system test indicating that the battery light on the dashboard and any of the charging system components being monitored are in proper working order.

The battery warning light will remain on if a fault is found in the charging system. When this happens, there are several probable causes to consider when troubleshooting.

Other symptoms may follow if the battery has difficulty charging, such as dim headlights. It may also cause the clock to run slow or other functions, such as the air conditioner or radio, to malfunction.

Remember to practice due caution when you work with electrical systems. Wear goggles and gloves for protection. Refer to your owner’s manual for pointers. Disconnect the car battery before you clean or examine it. 

What to Do If the Battery Light Turns on While Driving?

If the battery warning light turns on while driving, be aware that you probably don’t have too much time left to drive before your car dies on you. Try to drive home or to the nearest mechanic as soon as possible.

To make the most out of the remaining power in your battery, limit the number of car accessories in use. Shut down the air conditioning if not necessary. Unplug the phone from the charger and turn off the radio if you can do without it.

Do not turn the engine off until you have made it to your destination. The starter motor uses a lot of electricity, and the car won’t start if the battery does not have enough charge. Also, keep a close watch on the temperature gauge since overheating can also cause problems with charging.

Can You Drive Your Car with the Battery Light On?

You can drive your car with the battery light on but only for a short time. The light tells you that your car’s alternator is not sending enough power to the battery.

So, yes, you may still be able to drive your car. But the battery is not charging, which means that your vehicle will also eventually run out of power.

Conclusion – Causes for Battery Light on Dashboard

To reiterate, the causes why the battery light on the vehicle’s dashboard turns on are the following:

  1. Broken Auxiliary Drive (Serpentine) Belt
  2. Bad Alternator
  3. Broken Alternator to Dash Cluster Wire
  4. Faulty Dash Cluster
  5. Bad Battery
  6. Corroded Battery Terminals
  7. Broken or Corroded Engine Earth Strap
  8. Worn Alternator Pulley
  9. Loose or Faulty Battery Cable

The suggested steps for fixing the battery light on the dashboard are the following:

  1. Inspect the Battery
  2. Examine the Alternator
  3. Observe the Fuse
  4. Test the Battery

As soon as you see the battery light on your car’s dashboard illuminate while you’re driving, take the necessary steps to determine the cause. Make sure to address the problem immediately. If the issue is too extensive for you to fix on your own, call a professional mechanic to repair it for you.

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How Long Does It Take to Charge a Car Battery?

How to Recondition a Car Battery That Won’t Hold a Charge

Battery Positive Color and Negative Color – How a Car Battery Works

Best Place to Buy a Car Battery

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