4 Signs It's Time to Replace Your Alternator

Daniel McDonald
Daniel McDonald10 min read
4 Signs It's Time to Replace Your Alternator

Maintaining your electric vehicle is imperative to ensure its electrical components continue to operate properly. While many people tend to keep a check on their car battery, they don't pay much attention to the vehicle's alternator. As a result, they might not be able to pick the early signals of a failing alternator.

If your vehicle has a faulty alternator, you are likely to encounter some problems, such as the car not starting up or not staying on for too long. This sign indicates that you should now start thinking about getting a new alternator. You might not need a new alternator as frequently as a vehicle battery due to its exceptional lifespan.

However, ultimately the alternator fails, and you will need a new one to replace it. People often find it difficult to determine whether they need a new car battery or a new alternator. Both have different functions and have different symptoms, indicating they are not working well.

Therefore, you need to be aware of the signs to know if it is time to replace your alternator. We will discuss the four signs that indicate your vehicle's alternator is not working properly. But before that, let's have a better understanding of the functions of the alternator.

Functions of an Alternator

The alternator is an essential part of your car. It is an element of the combustion engine vehicle, and it helps transform chemical energy into electrical energy. The energy converted by the alternator will help refill the battery and provide it to other electrical components of your vehicle.

Since the engine is only responsible for providing mechanical energy, it does not produce electricity. Therefore, the car needs a power source that helps generate electricity and power all the accessories. For that reason, there is an alternator available in your car. It ensures all the electrical accessories in your vehicle receive enough power to function properly.

The car's electrical system comprises various elements that help keeps the car running, such as a battery, alternator, voltage regulator, etc. The alternator will convert the mechanical energy into an electrical one using an AC (alternating current).

The alternator is made of various components that allow it to generate an alternating current, such as the stator and rotor. Both these parts act as magnets and rotate to produce AC. The AC is then converted into DC (direct current) that the battery uses to charge itself.

In addition, the voltage regulator will send power to the battery from the alternator. It will manage the quantity of energy to ensure that the battery gets a constant flow of power.

Signs of a Failing Alternator

Now that you know the integral parts and the functions of an alternator, then let's move on to the signs that can help you identify a bad alternator. Generally, the car will cause difficulty when starting or won't stay on for too long.

The engine wouldn't receive enough energy to stay on, and the car will eventually turn off after a few minutes. This sign is an indication that you need a new alternator since the old one is not running smoothly. Here are four more signs to help you identify a faulty or failed alternator.

While multiple factors can cause the lights to become dim, the most probable cause is a failing alternator. In such a scenario, it is best to get a mechanic to take a look at your car. They can run a couple of tests to determine the actual problem and resolve the issue for you.

Bright or Dim Headlights

As the alternator starts to wear down and fail, it doesn't have the same capacity to operate as before. It will provide voltage to your electronic accessories and other components consistently. Consequently, it will cause some parts to function improperly.

Most notably, your headlights will either underperform or perform exceptionally well. They will either be way too bright or just too dim. In addition, the lights may start to flicker since they won't be getting a constant flow of voltage. These signs mean that you should get your alternator checked by a professional.

While other factors can also be the reason your lights become dim, the most probable cause is a failing alternator. In such a scenario, it is best to get a mechanic to take a look at your car. They can run a couple of tests to determine the actual problem and resolve the issue for you.

Issues with Electrical Accessories

Another sign that indicates a faulty alternator is problems with your electrical accessories. The most common reason for problems with electrical accessories, such as windshield wipers, power seats, power windows, etc., is due to a failing alternator.

Since the alternator is not providing enough power to the accessories, they often don't work properly or function slowly. If the windows take more time to go down or up, or if the power seats are not working properly, then there is a problem with your alternator.

Also, you can check the speedometer and the dashboard lights to see if they are working properly. If the dashboard lights are going on or off erratically, it indicates that your alternator is not running smoothly.

You will find modern vehicles with a program built-in to control the alternator if it does not provide enough power. The program has a list of equipment that directs the onboard computer to stop supplying power to accessories if the alternator is not working properly and not providing sufficient energy.

As a result, it ensures the vital part of your car continues to receive energy and operate as usual. You might notice the radio might lose power before the headlights go out. Similarly, all non-essential parts will stop working due to an alternator problem.

Most people tend to ignore the issues that are associated with electrical appliances. They are not able to pick the early signs of a failing alternator and ultimately get stuck on the road one.

As soon as your alternator stops working, you will have a short time to get to the nearest place. You'll have a dead battery since the alternator is no longer supplying power. Therefore, it is best to watch out for any issues with your electrical appliances.

Dead Battery

Another sign that helps you find out if you need a new alternator is a dead battery. Usually, a dead battery means that it has reached its full potential and needs a replacement. Other factors can be leaving the headlight on accidentally, exposure to extreme temperatures, etc.

However, there are a few instances your battery is fine, but it is the alternator that is causing the problem. A bad alternator won't be capable of charging the battery sufficiently when the engine is running. Therefore, the battery will deplete much more quickly than it does.

The best way to check whether you have a bad alternator or a dead battery is by jumpstarting your car. It will help you identify the issue with your vehicle's critical components.

The battery will need a replacement if you jumpstart your car and it is running. But, if the car dies shortly after you jump start it, then the alternator is faulty and needs a replacement. The alternator isn't able to provide sufficient energy to the battery, and that is why the car dies out shortly.

People find it challenging to identify if there is an issue with their battery or alternator. Since both cause the same problems, many people assume the issue is with their battery. Conducting the jump start test will help you find whether the problem is with your battery or the alternator.

Whining Sound or Foul Odor

You might find out too many sounds coming from your car. People don't tend to pay much attention to such noises since they consider them to be normal. However, some unusual sounds indicate there might be some severe mechanical issues with your car.

If you hear any whining and growling sounds coming from your car, it is an indication you might have alternator problems. Whining noises are something that you should not ignore, and you should get a professional to take a look at this problem as soon as possible.

The primary reason for this whining noise is the misalignment of the alternator belt. It rubs against the alternator's pulley, creating this strange sound. In addition, you will hear the growling sound if the bearings which rotate the rotor shaft is going bad.

Sometimes, you might not hear any sound, but you can smell a foul or burning odor. Since the alternator belt is close to the engine, it can wear out due to the heat. As a result, it releases an unpleasant burning smell. The smell can also come from the burning of wires near the alternator.

If the alternator has any frayed or broken wires that are not in the right condition, you will sense a burning smell. The odor will be similar to an electrical fire, and you need to get a mechanic to check it out ASAP. Prolonging this issue can cause severe issues to your car and can damage your battery.

Since an overworked alternator will try to pass too much electricity, the wires are likely to heat up. The frayed wires can lead to trouble starting the car and disrupt the electricity flow. It will cause the wires to release a foul odor similar to burning rubber or a cigarette lighter.

Repair and Replacement Options Available If Your Alternator Fails

If you have encountered the above signs and find out that your alternator is not working, you need to decide the next course of action. People have three choices to get their alternator working again:

  • Repaired

  • Rebuilt

  • Remanufactured

Each option has different complexities and will eventually determine the reliability of your alternator. So, if you hear someone saying that rebuilt and a remanufactured part are the same thing, they are wrong. Let's go over these options to give you a better idea.


The first thing that comes to our minds when we hear about a faulty alternator is getting it repaired. The repair option is about finding the parts in the system that are not functioning accurately and replacing them. You can head over to an auto repair shop, and they will take care of it for you.

They can also spot any parts that might fail soon and will replace them to avoid any issues. This option is preferable as many people find it less costly to get a few parts repaired. However, if too many elements need replacement, then it will make the repair option more expensive than others.

Moreover, if the alternator has failed previously, repairing it will solve the issue temporarily. You will eventually have to think about other options. It is better to discuss with your mechanic before proceeding with any option.


A rebuilt alternator has a lot more complex process than other options. First, the experts will dismantle the alternators and examine them for possible issues. They will test the electronic components and internal parts. Not all parts will require testing since some have a short lifespan and will eventually need replacing.

While a rebuilt alternator might look like a better option than a remanufactured one, it depends on the expert's capability. Their skills and practices will tell if the alternator is reliable in the long run or not.


Lastly, the third option is to remanufacture the alternators to get them in their original condition. There are rigid terms and processes that the remanufacturers must follow. The remanufacturers use the best and most robust equipment to test each component.

They will replace various components, including brushes, voltage regulators, etc. Most importantly, they will incorporate the new design changes that have come up since the manufacturer created the alternator.

Before choosing any of the options, you need to consider various factors and make the right choice. It is best to look at the bigger picture instead of looking for a temporary fix that can result in the same problems repeatedly. Therefore, you shouldn't hesitate to replace your alternator if it becomes faulty.

How To Know If There Is a Problem With Your Car Battery?

Usually, the issues many people face with alternators are similar to those associated with a car battery. Therefore, it might become challenging to identify which part is faulty. Issues like dim headlights and bad smell don't tell whether the problem is with alternators or car batteries.

However, a few signs tell you that your alternator works, but your car battery doesn't. You can check for the following signals to find out if there is a problem with your car battery.

Not Working Properly in Cold Temperatures

The car's electrical system, particularly the battery, will need more power to turn on during the cold season. Car batteries can freeze at lower temperatures and cause the chemical reaction to slow down. As a result, the battery dies out quickly in the cold season.

If that is the case, the problem is with your battery rather than the alternator. You can keep an eye on the dashboard warning light to know about the issues with your battery. The optimal thing to do is get a new battery before the winter season for an optimal driving experience.

Problems with Car's Electronics

If you see issues with your car's electronics, such as power windows, air conditioner, and interior lights, it is probably due to faulty batteries. You might notice your interior lights not working properly or the air conditioner not operating as efficiently as before.

Strange Odor Similar to Rotten Eggs

If the car's alternator is faulty, you might get a smell of burning rubber. However, you will smell an odor similar to rotten eggs if the batteries are not working. The reason for the smell is that the car's battery is leaking gas. Therefore, you will smell a strange odor in your vehicle.

Wrapping Up

Keeping a close eye on your car's alternator is vital since it is an integral part of the charging system that keeps the battery running. It can ensure your car's battery gets enough electricity to function adequately. Proper maintenance will play a crucial role in ensuring your alternators work properly.

If you see any issues with your electrical appliances, you should immediately check your alternator. It will help you identify a faulty alternator that you can get repaired without incurring heavy charges. Also, it is best to use quality parts when you go for the replacement option.

It will ensure the car's electrical system operates smoothly without any issues. You wouldn't want to go through the hassle of repairing the integral parts of your vehicle again and again. And if the technicians suggest replacing your alternator, you should give it a serious thought.

A new alternator will keep the car running smoothly and increase its efficiency. You can also enjoy using electrical appliances, such as radio, music system, etc., as they will continue to the required power to operate efficiently. The role of alternators is critical in the vehicle's charging system. So, it is best to check it for any issues.