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How To Check If Your Alternator Is Bad – Signs And Symptoms

How To Know If Alternator Is Out

Every part of your car is an important piece to a complicated puzzle. The alternator is no exception. The alternator is a generator that is crucial to the workings of your vehicle. Without the alternator working at optimal capacity, the electrical system within your vehicle will not be functioning correctly. A problem with the electrical system in your car can cause widespread damage and expensive repairs and replacements. If your alternator is bad, the charging system within your car will not be working – here’s how to check if your alternator is damaged or broken. 

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What Is An Alternator?


The alternator is a generator of electrical power within your car. It is a main component of your vehicle’s electrical and charging system. All cars with an internal combustion engine, minus a few select hybrides, have an alternator. When your engine is running in your car, the alternator is in charge of giving the battery power. The alternator is typically a maintenance-free generator of electric power. However, with poor care, you might have to replace or rebuild the alternator sooner than you think, despite the alternator typically lasting 10-15 years in most vehicles. 


The alternator also supplies electrical power to the vehicle’s exterior electrical systems to charge all of the components within the car. An alternator is bolted and secured to the engine and powered by the serpentine belt.


What Is The Serpentine/Drive Belt? 


The serpentine belt is also known as the drive belt. A drive belt’s function is to drive accessories installed on your engine. The drive belt will control and provide power to the alternator, water pump, and air conditioner compressor. If the serpentine belt breaks down or is damaged, the car won’t be able to drive. If you try to run the engine without the drive belt working, the engine would overheat, since the water pump isn’t working. The broken belt can also damage the radiator and coolant hoses. 


Symptoms of a broken drive belt include loud noises, squealing noises, and other sounds coming from beneath the hood. The charging system warning light could also come on since the alternator will stop charging the battery. A bad alternator and a bad drive belt go hand in hand. 


Symptoms Of A Bad Alternator


There are a few key signs of a bad alternator. The most common symptom is that the vehicle’s charging system will show an issue as the battery-shaped warning light comes on on your dashboard. If this light doesn’t come on, the “CHARGE” icon could also come on while you're driving. This warning light typically comes on when you turn the ignition, but it should turn off as soon as the engine is started fully.


If the light stays on, it is a clear indication that there is an issue with your charging system. The warning light doesn’t directly indicate a broken alternator, but it is the most common reason for the light. You should choose a mechanic to do some testing on the alternator and any electrical reasons for the light coming on while your engine is running. 


The second symptom of a weak charging system is if the dash lights and headlights dim while your car is idling, but turn brighter while the engine is turned on. The problem could be due to a weak alternator, but a battery that is dying could also be the reason. In addition, if there are poor connections with your battery terminals or a loose drive belt, that could cause a weak charging system. A whining and buzzing noise from the alternator is another symptom of troubles, and can be a sign of a noisy alternator bearing. 


The last symptom is failed plates within your car. There are three rotating plates that cover the vast space of copper wires, and creates the area for the alternator to produce power. If these plates fail, they can fail one at a time. This casuses the alternator to weaken, but not stop completely. If the plates fail, the power wil drop the output levels drastically. This wear nad tear on the electrical sytem causes ethe battery to fail, and the ignition system to die. In order to prevent the damage and destruction to your battery, you need to follow certain methods to check if your alterantor is bad. 


How To Check An Alternator


If you are unsure if your alternator is working to its full capacity, you’re going to need to run some tests on the part to see if it damaged, how bad the damage is, and how to fix it. The easiest way to test is by using a voltmeter, but there are other methods as well to determine the real issue with your alternator and if it is bad.


Method 1 – Using A Voltmeter


Step 1 – Buy A Voltmeter


The first step in the process of using a voltmeter is to buy a voltmeter – go figure. You can find one at any auto store or some department stores for usually less than $20. Don’t buy one of the most expensive brands because you think it will work better – the less expensive ones do the same exact job for a fraction of the price. 


If you already have a multimeter, you can use that instead. A multimeter can measure voltage and other electrical power within your vehicle, like the current and resistance. A voltmeter is a device used for measuring the electrical difference between two points within an electrical circuit. A voltmeter is a useful tool in determining if your car alternator is bad. 


Step 2 – Check Your Battery 


The second step is to first check your battery. Your battery is required in order to start and run your vehicle, which will, in turn, spin the alternator at a high enough speed to keep the battery charged and running. If your battery is too low or damaged, then you won’t be able to start your vehicle. If you can’t start your vehicle, you can’t test the alternator – it’s a vicious circle. 


Without being able to turn on your car, you can’t use the voltmeter to check the electrical power within your vehicle. If the weather is too cold or your battery has significant wear over time, the battery could be the real issue, and your alternator might not even be a problem. Here’s how to check your battery to ensure that your alternator isn’t bad, but your battery is. 


First, you’ll need to turn off the vehicle. Make sure your engine is off before attaching the voltmeter to prevent any potential accidents. Second, open the hood fully so you have access to the battery and other parts within your car. Third, connect the voltmeter to the battery. Set the red lead of the voltmeter to the positive terminal on the battery and place the black lead on the negative portion. Next, read the voltmeter. If the battery shows you ahe over 12.2 volts within your battery, then it has enough power to start the alternator. If the battery is below 12.2 volts, then you will need to charge the battery and re-test, or try a different method. 


Step 3 – Start Your Vehicle 


After you check the battery and ensure that it has enough power to start the alternator for the test, you can start your vehicle. Rev your engine to 2,000 RPM or above to ensure that your battery is giving power. This will increase the power, and force the voltage regulator to turn the alternator into a higher gear. If the alternator can’t turn into high gear, the alternator has gone bad.


Step 4 – Retest The Battery With The Voltmeter


Keep your engine running and re-test your battery with the voltmeter or multimeter you have. This time when you read the voltmeter, the voltage should read at least 13 volts. If changing the RPMs leads to a fluctuation in voltage between 13 and 14.5 volts, then the alternator is in working condition. If the voltage remains the same while the RPMs fluctuate, then your alternator isn’t working correctly and is in bad condition. Repeat this process with other electrical components on, like the lights and radio. If the alternator is charging and the battery stays above 13 volts, then the alternator is working well. 


Method 2 – Monitoring Your Alternator


Step 1 – Check the Alternator Gauge


The first step in monitoring your alternator to check the levels is to check the alternator gauge itself. If you have a voltage gauge, it will show the alternator output for you, and it will be easy to read and see the levels. Power the engine at least 2,000 RPMs for testing purposes. 


Turn the AC blower fan on, the headlamps and lights, and any other electrical accessories that will stress the alternator. Be sure to keep an eye on the gauge to see if it decreases sin voltage or amperage. If the voltmeter is higher when the engine is running, you can assume that the alternator is working well, and the alternator isn’t bad. 


Step 2 – Listen To The Alternator


While the engine is running, listen to the alternator. If there is a problem with the bearings, you could hear a squealing sound coming from the front of the car. The squealing sound will become louder when you have more electrical items on at the same time, such as the radio and air conditioning running simultaneously at a high power. 


Step 3 – Turn The Radio On


After you turn the radio on, rev the engine to a higher power. Tune your radio to a low number on the AM frequency band with no music playing. If the radio continues to whine or goes fuzzy when you press on the accelerator pedal, the alternator could be the issue, showing that your alternator is bad. 


Step 4 – Find An Auto Store


To determine if your alternator really is the issue, you should try to find an auto parts store that can test your alternator free of charge. Since stores will want you to buy an alternator from their specific store, they will be more likely to test out your original part for free – in hopes that it is faulty and damaged, and you will need to purchase a new one then and there. Dismount your alternator and bring it into the store for testing. 


How To Make Your Alternator Last Longer


Sometimes an alternator will fail before it is supposed to when the protective cover from the engine is damaged or missing. If water gets inside the alternator, it can cause it to wear faster over time. If the engine undershield is damaged, you need to replace it to keep the engine compartment dry. Additionally, coolant or oil can leak and damage the alternator. Be sure to keep the alternator and engine compartment dry to prevent liquid damage on the electrical parts. 


Alternator Replacement Cost


Replacing an alternator is an expensive process that typically runs between $420-$850. An original part bought directly from a dealer is even more expensive. Rebuilding the unit is cheaper, and requires your mechanic to remove the alternator and send it to a rebuilding shop. The mechanic will charge at least the removal and installation, which is $70-$120, the rebuilder’s charge, which is $80-$150, and sometimes extra labor prices. 


What If I Don’t Want To Go Through The Hassle To See If My Alternator Is Bad?


If your car is already old and there are other issues with your vehicle, you might not want to go through the trouble of bringing in your vehicle to replace or rebuild the alternator. Checking the alternator could take more time than you'd like, and you might just want to get a new car instead. If this is your thought process, then you should bring your vehicle to a reputable location to obtain a fair quote. At CashCarsBuyer you can bring in your vehicle, and earn some money for your vehicle without the stress and hassle of fixing the damaged parts. 


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