5 Signs of a Bad Alternator

What Does an Alternator Do?

An alternator works with your battery to charge your vehicle’s electrical systems. An alternator that’s going bad can affect your car in many ways. There are several signs you need to watch for that may indicate your alternator is bad.

1. Bad Alternator Sign #1: Flickering Headlights

It Still Runs states that dimming headlights is one of the first signs that your alternator is starting to malfunction. If you notice that as you increase or decrease the speed of your engine that your headlights will grow brighter and dimmer, this is a red flag. An alternator that is in good working condition will maintain bright headlights no matter what speed you are traveling.

Besides flickering, your headlights may also begin to weaken or grow dim. Lights that are dim across the dashboard are also indications of a problem. Both flickering and dimming are strong indications that your alternator is no longer capable of generating adequate power.

2. Bad Alternator Sign #2: Weak or Dead Battery

A battery that seems to be weak or has died may mean your alternator is going bad as well. An alternator can help replenish the battery in your car, but it can’t keep it going indefinitely. This means it’s important to distinguish between a weak battery and a bad alternator.

According to Nationwide, there are a few different ways to find out if you’ve got a dead battery or an alternator gone bad. Without starting the car, you can check the battery gauge on the dashboard. If it’s still sending out a strong charge, the battery is likely not the problem. It’s important to note that once an alternator goes bad the electrical devices will attempt to draw power from the battery, which in turn could cause the battery to die more quickly.

3. Bad Alternator Sign #3: Strange Sounds

An alternator has a lot of moving parts that spin when it’s working correctly. If one of these parts starts to work ineffectively or breaks off, you may hear some unusual sounds. If you’re hearing a grinding sound in your car, this could indicate that the alternator is going bad. The grinding sound may be caused by a worn-out bearing.

Your car can also make a whining sound when the voltage regulator is sending signals to the alternator to charge more than is necessary. If you hear any type of whining or grinding sound that’s a good indication that your alternator needs to be checked.

4. Bad Alternator Sign #4: Difficulty Starting Your Car

The alternator could be bad if your car won’t start or it’s turning over several times before finally starting. Of course a weak or dying battery could be the problem, but if you’ve already eliminated this possibility it’s likely your alternator isn’t working.

The Chicago Tribune reports that if the alternator has failed, a warning light will normally come on. Most vehicles have a specific light that is battery shaped that will come on to signal if there is an issue. Some may even say ALT. Alternators often have outputs between 13 and 15 volts. If it’s not working correctly the voltage can go below or above these levels, which will signal the warning light. In the beginning stages of a problem this light may come on and off sporadically.

5. Bad Alternator Sign #5: Electric Failures

Since the alternator is the primary source of electrical power in your car, electrical failures are signs that it is going bad. Electric failures could present themselves in a variety of ways. Your power windows could operate more slowly. Other items that could be affected include power locks, windshield wipers and heated seats.

While these are all signs that your alternator is going bad, to know for sure you’ll need to have it tested. There are home tests that can be conducted but to know for sure what problems are occurring and how to fix them effectively you should have your car tested by a trained mechanic.