How Do You Know when Your Alternator is Bad?
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How Do You Know when Your Alternator is Bad?

Determine when your car alternator is bad. By doing so you can save yourself hundreds of dollars in repair costs! Your alternator enables your vehicle's electrical components to function by providing electrical power to them. When your vehicle begins to act up by not starting, or stalling after it has started, chances are you may have to replace your alternator.

A failing alternator does show a number of warning signs before it dies. The first of which, and most obvious, is the status of the electrical components in your vehicle. If you begin to notice that your vehicle’s dashboard lights grow dimmer at times and act normal other times, there is a high chance that this is being caused by a failing alternator. 

The next warning sign you may notice when your alternator is bad, is the vehicle may not start or it completely stalls while it is running. When this happens to your vehicle, you have to perform a few tests in order to make a sound diagnosis, as this problem can be caused by a number of factors. Most times this problem will be caused by your alternator, your alternator belt or your battery. To figure out the exact cause of the problem, there are a few diagnostic tests that you can undertake.

First, you have to determine if this is being caused by a faulty alternator belt. If your engine belt is loose, the belt may not be catching properly.  The belt’s role is to rotate the alternator, which then produces electricity for the electrical components of your vehicle. If the belt is loose, off of its track or damaged and cracked, it will not perform its function properly with the alternator. If your vehicle has stopped running, first check your serpentine belt to determine if it is the cause.

If your belt seems to be in fine working order, than we can being troubleshooting other common problems. Next you will want to inspect the battery. First check to see if any battery cables have become loose or corroded. If the connections seem secure and free of corrosion, you will want to perform a voltage test on the battery. After your vehicle has been sitting for a night, hook up a voltmeter. If the battery is in good working order, you will get a reading between 12.5 and 12.8 Volts.

To determine if your alternator is bad, you will want to use the voltmeter to check the output of the alternator. Hook up the voltmeter the same way you did for the battery test and turn it on. Have someone start your vehicle, turn on the headlights, and press on the acceleration until it reaches 2000 RPMs. Ideally, you would like to see a reading between 13.6 Volts and 14.3 Volts, but as long as it is over 13 Volts you should be fine. 

If you are unable to troubleshoot the cause of your problem and you are able to get your vehicle to the shop, many repair garages will perform an alternator test free of charge. However, with the warning signs in place, and by conducting the proper tests, you should be able to determine when your alternator is bad.

For More Info: Car Alternators

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