Have you gotten the alternator warning light and you are asking yourself how to tackle this problem before it’s too late and your car stalls? Well, if this is the situation you are into, then you are at the right place because there will be a lot to cover on this topic.
Having a problem like this with an alternator that is not charging well can be really frustrating to deal with. Why I’m saying this? Well, because it is true. Nobody wants a problem like this because when an alternator is not working as it should, a lot of troubles can happen.
Namely, your car can stall and you will basically be prevented from driving the vehicle. And you don’t want that. Especially when it comes to something simple such as an alternator. Alternators, although they might look scary, they are rather simple to troubleshoot and diagnose with a multimeter. And even by the audible symptoms, they produce. But more on this, we are going to cover later on in the article.
First, we will learn what is an alternator and why it is so important. Then we will take a look at the alternator warning light and after that, we will cover the bad alternator symptoms (thus, the importance of learning how to know if alternator is bad). Once we cleared all of the symptoms we are going to discuss how you can tackle this issue and diagnose a bad alternator and also how much money it will cost you. So, if you want to learn more about this. Please follow along.
What Is An Alternator?
Now before we dive into the alternator warning light and why it appears. Let’s first take a look at what is an alternator in general. I bet that there are people who are reading this article and do not know the basics when it comes to these components on the car. So, what is an alternator in general?
Well, an alternator in simple words is an electric generator that generates AC current also known as the alternating current which later is converted into DC or direct current since all the accessories and the engine work on DC current.
Nevertheless, in the past there were dynamos. They served a similar purpose but they were all heavy and really unpractical. So, something new and more compact had to be invented. And this is how the alternator was invented.
At first, it was used for military use during WW2 but after the war, it was introduced in cars and became one of the most irreplaceable components. And frankly, it hasn’t changed a lot during long decades of use.
It is still the same good old design with a rotor and a stator. The rotor is rotated with the help of the crankshaft and as it spins it creates an AC current. Simple as that. Even though it might sound simple the work of the alternator. Actually, behind the curtain, the function of this component is much more complex since this is basically a generator that creates an electrical current.
And when it doesn’t work well, you will get the alternator warning light. But before we cover the warning light, let’s discuss more about the importance of the alternator and its diagram.
Why The Alternator Is So Important?
Now before we discuss the alternator warning light. Let’s learn more about the function of the alternator and why it is so important. This will be a good input for you on the function of this component and will help you understand better its main method of action and how it works behind the curtain.
As we explained previously, the alternator is a component that is generating alternating current AC. Thus, the name alternator.
This alternator has a stator and a rotor inside of it. The stator is the static component which is composed of a magnet and copper wires. Then in the center is the rotor which rotates around its shaft.
Then this AC current goes through the rectifier. The rectifier is an important component that converts the AC into DC. And this conversion is essential if you want to have a properly working alternator.
On each alternator, there is also a voltage regulator. This voltage regulator is essential because this component controls how much electricity the alternator can create. So, the maximum output alternator voltage should be between 13.5 and 14.7 volts.
Anything above this and below this can be considered to be a bad alternator. Or a bad voltage regulator of the alternator.
In addition to this, there will be bad alternator symptoms that we are going to cover later on that are tell-tell signs that you have a bad alternator. And one of the consequences of a bad alternator is the alternator warning light that we will cover next.
Alternator Warning Light
Now let’s cover the alternator warning light in detail since that’s why we are here after all. What is this light? Well, this light is one of the most important symptoms that will tell you that you have a problem with the alternator.
This light is also known as a battery light as well (which explains why you’re seeing the battery symbol on your car or the Honda Odyssey battery light). But why is this the case? Well, this is the case because this light turns on when either of these components performs poorly.
So, whenever the alternator warning light turns on, you are not able to tell right away if you have a problem with the alternator or possibly with the battery.
This is why when you see this light, you shouldn’t instantly think that the alternator is bad and that you need to pay hundreds of dollars to replace it.
It could be the battery that is faulty and doesn’t hold power. This is why proper diagnostics is really essential when it comes to this situation if you want not to misdiagnose stuff and change components in a hurry.
Later on, we are going to cover how you can diagnose a bad alternator and also a bad battery. Now let’s cover another topic which is the bad alternator symptoms. You need to know the symptoms before you decide on replacing the alternator on your car after all and that’s why we are going to cover all of them in detail.
Bad Alternator Symptoms
Now let’s dive into the bad alternator symptoms. In the following chapters, we will cover every possible symptom of a bad alternator.
Knowing the symptoms will help you out when it comes to diagnosing this component on your car and determining if the alternator is indeed broken or if the root of the problem with the alternator warning light is something else. So, let’s get into it.
1. Battery Light Or Alternator Warning Light On
The first symptom of a bad alternator is the battery light. Also known as an alternator warning light. As we mentioned above, this light is basically in charge of both of these components.
So, whenever you have a bad battery you will get this battery light as well as when the alternator is broken again you will get the battery light. Now, in order to not repeat ourselves, let’s move on to the next symptoms.
2. Not Charging Battery And The Alternator Warning Light
The second most common symptom of a bad alternator and alternator warning light is the situation when your battery is constantly empty.
A bad alternator is not charging the battery as it should and it will be constantly empty if this is the case with your car.
So, if you notice that your battery is fairly new and the car doesn’t crank from the first try, you might have a problem with an empty battery that cannot deliver the cranking amps or problems with spark plugs, ignition coils, or possibly you have a parasitic loss from some of the components in your car that is draining the battery.
All the scenarios in this situation need to be checked and you need to diagnose which of the components is causing this issue. The first thing that you will need to do to tackle this problem with the alternator warning light is to measure the voltage that your battery has with a multimeter.
This way you will be sure if you have 12.6 volts when cranking the engine. If you don’t have this voltage, then you need to test the alternator. And how you can perform this work we are going to elaborate more in the following chapters after we cover the bad alternator symptoms.
3. Car Stalls And Doesn’t Want To Start
The next bad alternator symptom that could trigger the alternator warning light is the situation when the car stalls and doesn’t want to start. So, why is this the case?
Well, this is the case because the alternator isn’t working anymore. Once the alternator does not produce enough electricity, there will be a lack of power for the combustion to be complete and the spark plugs will simply stop working. When the spark plugs stop working, the car simply dies.
Both your battery and alternator in this situation will not work. This insufficient work of the alternator will drain the battery of your car and the car will stop.
Even if you try to jump-start this car, you will be unsuccessful because there will be no generation of electricity so the engine to start and continue working.
This is why when you notice the alternator warning light and your car stalls all of a sudden unable to run, it means that the alternator is probably dead. Or the serpentine belt has snapped that drives the alternator. This is an option as well, so check under the hood to make sure that the belt is all well. Now let’s move to the next alternator warning light symptoms.
4. Alternator Producing Strange Noises
The next in our list of bad alternator symptoms and the reason for alternator warning light is the situation when the alternator is producing strange noises.
A ton of people notice the alternator clicking and think that the alternator produces this sound. But actually, this is not true. The clicking sounds are produced by the starter motor that doesn’t have enough power from the battery and starts clicking.
On the other hand, when the alternator fails, it starts to produce whining or grinding noises. These noises will be more and more present when the alternator is close to failure. But why is this the case? Why there are noises when the alternator fails?
Well, this is the case, mainly because the alternator has a shaft inside. And this shaft rotates with the help of bearings. When the bearings are worn out. The stator and rotor come in contact with each other and here major damage occurs. This is why noticing the alternator warning light on time is key if you want to avoid alternator replacement since these components can be rebuilt (rather than needing to figure out how to change alternator and how to replace alternator and changing the alternator). Not to mention, accounting for the alternator replacement labor cost.
5. Serpentine Belt Is Loose Can Trigger Alternator Warning Light
The next symptom of a bad alternator and the alternator warning light is the situation when you have your serpentine belt loose.
This can be attributed to a bad alternator shaft and the serpentine belt could get loose and you will have a ton of trouble running the car’s alternator. But why is this the case?
Well, this is the case because the belt will slip. This means that it will not spin the pulley well enough to allow a proper charge of the battery.
The serpentine belt of the alternator needs to be tight enough to allow proper work of all of the pulleys. If one of them is bad, like in our case with the shaft of the serpentine belt.
It means that you will have a ton of trouble charging up the battery and your alternator will perform poorly causing the alternator warning light to appear on the cluster. But more on the diagnostics later in the article. Let’s first finish the bad alternator symptoms.
6. Burning Smell Coming From The Alternator
Another symptom of a bad alternator that will trigger the alternator warning light on the dash is the burning smell.
This happens on alternators that are overworked and have some fault with the voltage regulator. If the voltage that the alternator is producing is too high it could lead to catastrophes.
A bad alternator could easily turn your car into ashes if you don’t fix it on time. This component is safe in most situations but in some situations when the voltage regulator fails it can push too much electricity through the wires and the wires can easily melt.
This could cause a burning smell coming from under the hood. What is important for you is to stop immediately once you notice this type of smell and make sure that you have a fire extinguisher next to you. Sometimes these components can catch fire and make your car burn to the ground.
So, always have one small fire extinguisher next to you in case of emergency. Now let’s move to the next symptom before we learn more about the alternator warning light.
7. Lights Are Dim Or Flickering
And the last symptom that we are going to cover before we dive into the diagnostics and learn how to diagnose an alternator warning light is the situation with the dim lights in your car.
Whenever the alternator is not working properly, you will get a voltage that is not sufficient let’s say to power the headlights, stereo, infotainment, and dome lights. In this situation, these components might start to glitch.
The headlights will get dimmer and dimmer and you will barely see in the night. The dome lights will flicker or not turn on at all.
Also, the infotainment system or stereo will continuously restart under these circumstances. Which is a clear sign that something is going on with the alternator. But how you can test an alternator on your vehicle? Well, that’s what we are going to learn in the following chapter, where we will dive deeper into this problem and learn how we can diagnose alternator warning lights. So, follow along.
A ton of people who are having this problem with the alternator warning light are asking the same question. Battery or alternator? What could be causing this problem with the alternator warning light in the first place? Let’s explain.
The easiest way that you can check if you have a problem with the battery or the alternator is to turn on your car. Preferably during the night.
Then turn on every possible accessory in the car. The headlights, dome, lights, stereo, everything possible. If the components start to glitch and turn on and off, then you definitely have a problem with the alternator. The alternator simply doesn’t makes sufficient power to make sure that all of these systems work.
Another method that you can try which is better, is by using a multimeter. And this is dead easy to do. You only need to tweak the multimeter and set it up to measure volts.
Then place the black probe in the negative terminal of the battery and the red one in the positive terminal. A good battery should always give you 12.6 volts on average. 10V or 8v can mean that one or two of the battery cells are dead. So, keep this in mind.
But how you can test the alternator? Well, the alternator testing is also pretty straightforward. You do the same thing as in the case when you test the battery with the multimeter and probe placement.
But the only difference is that now you start the car. A healthy alternator with zero appliances working inside should produce between 13.5 and 14.7 volts. If you turn on the headlights and radio, you could lose a volt or two but this isn’t something that you would worry about.
Cost To Replace An Alternator
When it comes to the cost of fixing the alternator warning light and replacing the alternator. Prices may vary to a good extent.
For some cars, alternators can be as cheap as $250. But for some cars, they exceed $600 or more in some cases. This greatly depends on the type of engine that you have. So, you can expect prices between these two figures.
Also, the labor prices will be between $150 to $300 to replace this component on your car.
Conclusion To Alternator Warning Light
In this article, we have covered quite a bit when it comes to the alternator warning light. First, we learned what is an alternator and how it works. Then we elaborated on the alternator warning light and the other symptoms of a bad alternator.
Then we learned how you can diagnose a bad alternator with a multimeter and the costs that will be involved in the replacement of this component.
F.A.Q To Alternator Warning Light
Now let’s answer some frequently asked questions.
Where Is The Alternator
The alternator is located on the side of the engine. Sometimes it is tucked in the bottom portion of the engine bay and in some cars, it is up and visible. It really depends on what car you have to get to the exact location. The best tip is to browse your engine and the phrase alternator location to find it based on images.
What Does An Alternator Do
The alternator in simple terms is a generator. The alternator generates alternating current AC which is then converted into DC current and is used to power all of the accessories in your vehicle as well as power up the engine ignition system.
Why Is My Battery Light On
There could be two reasons. Either the alternator is broken and is not functioning as it should. Or your battery doesn’t hold a charge anymore. Both of these options are on the table and you need to dive deeper to diagnose the real cause.
How To Tell If Alternator Is Bad
You can tell if an alternator is bad if you measure the output of the battery when the car is working. For a healthy battery and alternator, the voltage should be between 13.5 to 14.7 volts. If it’s lower than this, then your alternator is probably not working as it should.
What Does The Alternator Warning Light Indicate
This light indicates that there is a problem with either the alternator of the car or the car battery itself. For more precise information on which of these two components is bad, you will need to test them with a multimeter and determine if the voltage they produce when the car is working is at the required level of 13.5V to 14.7V.
How Long Does It Take To Replace An Alternator
For a skilled mechanic, I would say about two hours max. There are cars that are rather complex and can be really tricky to get to the alternator. So, it really depends from application to application. The most time would probably be about 4 hours.