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Alternator Problems

Alternator problems are fairly common. You will probably have some type of problem with your alternator in your cars lifetime. The charging system on your car plays an essential role in everything electrical. If your charging system is not working correctly it can cause major electrical problems so it pays to know a little bit about it. Let’s look at what they do and how to tell if there is something wrong.

What does an alternator do?

Their main purpose is to maintain the battery. Basically what happens is that it uses the engine power to create electricity and sends it over to the battery to keep it fully charged. Engine power is sent to the alternator via the engine drive belt, aka serpentine belt. This is why it is so important to keep the belt tight and replace it when needed.

When you are driving your car with all the lights on, the windshield wipers on and the radio blasting it uses a lot of electrical power. If all you had was a battery all of this electricity useage would drain the battery in a matter of minutes (sometimes more like an hour depending on how good of a battery you have.). To keep this from happening and to keep our battery in a state of full charge we us an alternator.

What are some common alternator problems?

It can be very tricky to diagnose these problems without any tools. Battery problems often seem like alternator problems and vice versa. Some of the most common things that happen are things like your car not starting, your battery going dead, serpentine belt squealing and battery light on. These are the most common, but there are others as well.

How can I tell if mine is bad?

There are several ways to tell if yours is faulty. You can do it yourself if you want to buy the tools (You can find them in my store) or you can have an auto parts store test it. Most will do it for free.

If you want to do this auto repair yourself, or diagnose it yourself then you just need to get what is called a digital volt ohmmeter or DVOM (aka voltmeter). This tool is available in my website store. With this tool you can quickly and easily see how much voltage your alternator is putting out.

The first thing you should do is turn your engine off. You will need to start your car for a later test, but for now just leave it off. Take your voltmeter and put the red lead on the positive post of the battery and the black lead on the negative side of the battery. Be sure your voltmeter is set to read DC volts. It should read above 12.65 volts. This would indicate that the battery is fully charged. If it is not then you either have alternator problems or a battery that is faulty. The next thing you need to do is to remove the leads from the battery and start your car. Then put the leads back on being careful not to get them caught in the serpentine belt or any other part of the engine. Read the voltage with the engine on. It should read somewhere in the 13.5-14.5 volt range. If it does then most likely the alternator is just fine. It is possible that it is still bad though, sometimes they are intermittently bad. If it proves to be good then you probably have battery problems. It is time to get the battery tested.

What should I do if mine is bad?

You can either repair it yourself or take it to a repair shop. Performing this auto repair yourself is usually not too hard, but will probably require a few special tools. You usually need a special tool to remove the serpentine belt. I highly recommend using an online repair manual to get all the information and diagrams you need for this job. You will definitely need a serpentine belt diagram so you can be sure to put it back on correctly.

This auto repair pretty much just requires that you disconnect the battery, remove the serpentine belt, then unbolt the alternator and remove the wiring connectors. Then just do everything in reverse to re-install it. If you decide to take this auto repair to a repair shop it usually does not cost very much to have them repair it for you.