Battery Light On In Car

Battery Light On In Car: Possible Reasons And Solutions

The battery light in your car is also known as a dashboard battery indicator. When this battery indicator is on, it tells us something is wrong with the battery and charging system and needs to be addressed.

What are the possible reasons behind the battery light on in car? It generally illuminates when the battery is dead, battery connections are loose or damaged, alternator issues, and many more. Too many accessories and ground straps can also be the culprit.

But how do we fix these issues? Which issue should you inspect first? Read on to find out the answers for precise knowledge.

A Quick Overview of the Possible Reasons and How to Fix Battery Light On in Car

Possible Reasons and How to Fix Battery Light On in Car

Take a quick look at the possible reasons and solutions for this particular issue:

Battery IssuesDead BatteryReplace the battery
Loose or Damaged Battery CableSecure loose connections and replace damaged wires
Corroded Battery TerminalClean corrosion from the terminal
Alternator IssuesWorn-Out AlternatorReplace the worn-out alternator
Faulty Alternator PulleyInstall a new alternator pulley
Damaged Alternator BeltSwap the damaged belt with a new one
Other IssuesToo Many AccessoriesReduce the use of additional accessories
Wiring Issues in Car’s Charging SystemInspect the wires and fix
Defective Engine Ground StrapReplace the defective ground strap

What are the Possible Reasons Behind Battery Light On in Car with Their Solutions?

Battery Light On In Car

You may face battery light-on problems for multiple reasons. Some of the common reasons are given below:

Battery Issues

If you notice the battery light on in car while driving, the first problem it may indicate is battery issues. Since the battery light is directly connected to the battery, we will start by inspecting this issue:

Battery Issues

1. Dead Battery

A car’s battery light is designed to illuminate when the battery is worn out or there are any issues with the charging system. 

So, it’s common that you will probably see this specific issue when your car battery is dead. Lost charge, sulfation, temperature damage, and battery lifespan are common issues behind a dead car battery.

2. Loose or Damaged Battery Wire

Over time, battery wires can come loose or get corroded, contributing to the battery light-on issue. The loose battery connection fails to maintain strong contact between the battery light and the battery terminal.

Additionally, loose connections or corroded cables may not draw enough power to run functions smoothly but enough to drain battery power.

As a result, you may see the battery light flashing due to the battery wires issue.

3. Corroded Battery Terminal

A battery terminal with corrosion is a common scenario in old cars. Corroded battery terminals can also influence the battery light on in car issues.

Corrosion builds up between the terminal and cable increasing electrical resistance. This prevents the full cranking power of the battery from reaching the starter motor.

Additionally, corroded battery terminals may not be able to draw enough power. Therefore, it creates unstable voltages that confuse the computer function, and this particular problem occurs.

Car Battery Issues


To solve this problem, you need to follow the below solutions:

  • The battery is usually located under the hood. Now disconnect the negative and positive clamps and remove any holders. Take out the battery and install the new one. Reverse the opening process.
  • Inspect all the connected wires to the battery and check whether any wires are disconnected or frayed. Consider securing loose connections and replacing damaged wires.
  • Remove the terminal clamp bolts. Clean the corrosion from the battery and clamp terminals using a wire brush or sandpaper. You can use a thin coat of petroleum jelly, Noalox grease, or anti-corrosion spray to clean battery terminals.
Read:  Battery Light Comes On Then Goes Off When Accelerating

Alternator Issues

If the battery is running fine and you’re still experiencing battery light issues, move on to the alternator compartment. Here are some problems regarding alternators that contribute to the issue:

Alternator Issues

1. Worn Out Alternator

The alternator charges the battery. If the alternator malfunctions or wears out, it can’t fully recharge the battery after use.

When the battery isn’t recharged, its voltage will drop over time to a level that triggers the battery light. As a result, you will see the battery light on when the car is off and while driving.

2. Faulty Alternator Pulley

This issue can also disrupt the charging system of the battery. When the alternator pulley is defective, it fails to spin the alternator properly and generate sufficient power. 

Plus, it fails to transfer motion from the serpentine belt to the alternator, which hinders the charging process. The battery receives an inconsistent charge from an alternator not spinning at optimal rpm due to a faulty pulley transmission.

3. Damaged Alternator Belt

The alternator belt can develop cracks or get damaged over time. As the alternator functions for charging the battery, a damaged alternator belt can’t spin the alternator efficiently to charge the battery. 

Over time, with incomplete charging cycles, the battery level drops low and turns on the battery warning light.

Car Alternator Issues


Here is how to solve these problems:

  • Disconnect the negative cable from the battery and other cables from the alternator. Loosen the belt tensioner pulley bolt and remove the drive belt. Now, swap the old alternator with a new one.
  • First, remove the alternator belt. Locate and remove the pulley mounting bolts, pull out the old defective pulley, and install the new one. Reinstall the part you disconnected.
  • Locate the belt routing diagram for your car. Loosen the tension on the belt by loosening the tensioner pulley bolt or alternator mounting bolts. Remove any belt guards or covers to access the belt fully. Now install the new belt after removing the old one.

Other Issues

In case the battery and the alternator are working optimally, then there are probably other issues. Such as —

Car Other Issues

1. Too Many Accessories

Most car owners love to add accessories to their car to make it look aesthetic or improve the system. But some accessories need more power from the battery to run. Such as:

  • LED lights
  • Winches
  • Auxiliary lighting equipment
  • subwoofers

So, when too many accessories draw power at once, they also overload the alternator by pulling energy. Thus, it can’t effectively charge the battery, which eventually causes the battery light to activate.

Read:  How to Check for a Draw on a Car Battery With a Test Light?

2. Wiring Issues in Car’s Charging System

Your car’s charging system includes many wires to draw power from the electrical circuit. 

If any included cables are damaged or disconnected, the battery will experience interruptions when drawing power and charging. Some of these wires are —

  • The main battery positive (B+) terminal wire connects the alternator output terminal to the battery. It transmits huge power to the battery.
  • Field wire that connects the alternator’s field coil to the ignition switch.
  • Regulator wire that connects the battery to the alternator voltage regulator.

3. Defective Engine Ground Strap

Ground strap wire is another essential cable for the battery that connects the alternator’s housing to the vehicle’s chassis. Ground strap wire is also considered as the negative battery wire.

This cable directs the route for the power to flow back to the battery. To transmit power properly through the cable, the engine ground strap must be functional. 

If the ground strap is faulty, it’ll lead to low voltage, and the battery will fail to operate effectively, causing the battery light to illuminate.

Car Issues


Follow the below steps to solve these problems:

  • Disconnect additional accessories in your car.
  • Inspect the wires of the mentioned components and ensure a secure connection. If you find any corroded or frayed wire, consider replacing it. 
  • When the ground engine ground strap is defective, you need to replace it. First, locate it and disconnect the battery cable clamps. Remove the bolts and replace the old ground strap.
If you’ve encountered the issue of the battery light coming on in your car, it’s essential to address it promptly. To understand why the battery light came on while driving and how to deal with it, read our informative article on battery light came on while driving. Additionally, if you drive a BMW and need to know how to reset the brake light, our guide on how to reset brake light on BMW can be helpful.


Here are some commonly asked questions regarding battery lights on in cars:

Q: What does the red battery light mean?

The red battery light means there is a problem with the charging system, and the battery is not being charged correctly.

Q: How long can you drive with the battery light on?

You should not drive the vehicle for an extended period with the battery light on, as it could leave you stranded once the battery dies.

Q: Is it safe to drive my car with the battery light on?

It’s not safe to drive the car for a long time with the battery light on. It indicates a problem that needs to be diagnosed and repaired. But, short driving with an illuminated battery light is okay.

Q: Why is my battery light on with the new battery?

If the battery light comes on with a new battery, it likely means there is still an underlying issue with the alternator or charging system that needs to be fixed.


So, you now have ideas on the possible reasons behind the battery light on in car issues. You also know how you can solve this problem by yourself. However, you should consider help from a professional mechanic if you have never fixed car issues.

Without expertise, you may end up causing more damage to the battery or charging system as it involves lots of wires.

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