Five-Star Manufacturer
Fast Delivery
Customized Service
HomeTips & GuidesWhat Does The Alternator Warning Light Mean?

What Does The Alternator Warning Light Mean?

What does the alternator warning light mean? Is the alternator warning light on your dashboard on, but you aren’t sure what the problem could be?

 Several different problems could result in your alternator warning light turning on. The article will help answer the question.

Table of Contents

What does the alternator warning light mean?

An alternator warning light is often referred to as a battery light.

The light will turn on once you start the car, and if the light quickly turns off, this is a sign there’s no issue with your vehicle.

However, if there’s an issue with your battery or your alternator isn’t charging your battery properly, your dashboard will display a light.

In most cars, the battery light is usually orange or red in color.



Why is the alternator warning light on?

Below are some of the reasons your car battery light is on.

Your Car Has a Weak Battery

Although you can expect your battery to last up to four years, it will generally weaken, especially if you use it in hot temperatures. 

Your battery light will turn on if your battery is nearing its end. 

Your Car’s Alternator is not working as it should

You’re probably aware that your alternator keeps your battery charged as you drive around. 

Normally, an alternator will last you up to four or five years. However, as the alternator ages, it can no longer properly perform its duties.

 If your alternator completely dies, the remaining power in your battery will deplete in a few minutes.

The battery light will turn on whenever there’s an irregularity in the charging. 

Your Car’s Alternator Belt is not Working Properly.

An alternator belt makes the connection possible between your alternator and crankshaft

Therefore, if your alternator isn’t properly functioning, the battery won’t get the necessary charge to power your car’s electrical system, resulting in the battery light frequently turning on.

Your car’s ground wire is malfunctioning.

Your car’s ground wire interfaces with the battery’s negative terminal. 

Although rare, your ground wire loosening up or undergoing damage could be why your battery light is turning on.

Any damage or looseness affects the capacity stream to your car’s electrical system, thus turning on the battery light.

The Overuse of a Large Number of Car Accessories

The car battery is responsible for powering your car’s entire electrical system. 

Besides the massive power requirements of radiators and air conditioning, your battery must also power GPS navigation, telephone chargers, cellphones, and car players.

Any extra electrical components deplete the battery’s power faster, leading to the battery light on.

Man Putting Out Engine Fire With Fire Extinguisher

Man Putting Out Engine Fire With Fire Extinguisher

How to make sure the problem is with the alternator?

As mentioned above, if the warning light turns on, it indicates a problem with your alternator or battery. However, how to troubleshoot the problem?

The battery is in good condition, but the light is on.

Often, if your alternator is faulty, it’s unable to properly charge your battery, which could leave you with a dead battery. 

Therefore, if you have a fairly new battery, you could have a dead battery or a problem with the spark plug or ignition coils that hinder the battery from charging. 

Before fixing any problems, you should use a multimeter to check your battery’s voltage.

 If the voltage isn’t 12.6 V when you crank the engine, you should proceed to check your alternator.

Car Stalling and Failing to Start

Once your alternator is nonfunctional, it can’t produce sufficient electricity. 

Therefore, there’s not enough power for combustion, and your spark plugs stop functioning, and once your spark plugs fail, your car will die.

In such a scenario, despite countless attempts to jump-start your car, nothing will change because your alternator isn’t producing electricity to keep your car running.

Strange Noises

If your alternator is faulty, it might produce some grinding or whining noises that become increasingly significant as the alternator approaches critical condition. 

Often, people assume that the clicking sounds are attributed to the alternator just doing its job. However, this isn’t the case. 

The clicking noises can result from your starter motor not getting sufficient power from your battery.

Since alternators have a shaft that spins with the assistance of bearings, you could have worn-out bearings. 

Therefore, the rotor and stator contact one another, causing catastrophic damage. 

The Serpentine Belt is Loose

If the serpentine belt is loose, it could slip, resulting in the pulley not spinning enough to properly charge your battery.  

A Burning Smell

Generally, alternators are safe; however, pushing high voltage levels through your wires can melt the wires, causing a burning smell in your hood. 

Flickering or Dim Lights

If there’s a problem with your alternator, your car’s electrical headlights won’t get sufficient voltage and get dimmer with time. 

On the other hand, your dome lights may begin flickering or completely fail to turn on. 

Also, under such circumstances, your car stereo might keep continuously restarting.

How to test the alternator?

The most straightforward way to determine if the problem is with your alternator or battery is simply turning on your vehicle, preferably at night. 

Then, turn on all the components in your car, such as the stereo, dome lights, headlines, etc. 

If any of your components flitch and eventually go off, there’s an issue with your alternator.

 It means your alternator isn’t producing enough power to power your car’s electrical system.

Another method to test your alternator is tweaking your multimeter to test the amount of volts. 

Then, place the red probe on the battery’s negative terminal and the black probe on the negative terminal. 

A fully functioning battery should measure an average of 12.6 V. However, measuring 8 V or 10 V could signify that one of the cells is dead. 

When testing your alternator using a multimeter, the procedure is the same regarding probe placement; however, you must turn on your car for this one. 

A good alternator with no electrical components turned on should measure around 13.5 V – 14.7 V. 

After turning on a few electrical components, you should expect to lose a few volts, which shouldn’t alarm you.


When people notice the warning light on their dashboard is on, they’re confused about whether the problem is with their alternator or battery. 

It’s always best to tend to the problem immediately, as some of the problems could be catastrophic. If you have any further queries, please contact Cloom Tech.

I am Lillian Yang, having been a sales manager for over 10 years.

I have received many positive reviews from customers. They have praised our excellent service, on-time delivery, and high-quality cable assemblies.

For your projects, please provide cable assembly files/images/smples, etc., so that I can send you a quotation within 24 hours.

Contact me now and let’s get started on building your wire harnesses!

Background media

For Better Future
and Business
Let’s Talk Now!

Fill in your details and we’ll get back to you in 24 Hours.

Contact Form Demo


[email protected]




3rd Floor, Nanhai Plaza, NO.505 Xinhua Road Xinhua District,
Shijiazhuang, Hebei, China. 050057


© 2007- 2023 Cloom tech. ALL RIGHTS RESERVED.



Subscribe to our newsletter for the latest updates, exclusive offers, and exciting news delivered straight to your inbox.