What Does the Alternator Warning Light (Battery Warning Light) Mean? | YourMechanic Advice

What Does the Alternator Warning Light (Battery Warning Light) Mean?

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The alternator on your vehicle uses the rotational power of the engine to generate electricity and keep the car running. The alternator needs to maintain a certain voltage in order to keep the battery at sufficient charge while driving. As the alternator ages, it won’t be able to maintain a constant voltage and any fluctuations will be detected by the car’s computer.

What the alternator warning light means

When you start the engine, the car will check to make sure the alternator is outputting the correct voltage. This warning light will shut off after a few seconds if the computer has determined that the alternator is functional. When the light stays on, it indicates that the computer has detected an issue with the charging system.

If this light illuminates, try to use only necessary accessories like windshield wipers or headlights so as to avoid excessively draining out the battery. An alternator that is on its way out may cause this warning light to flash when there is a high demand on the battery. You can always save yourself a lot of trouble by paying attention to warning signs like this and trying to conserve your car’s battery.

What to do when the alternator warning light is on

As mentioned before, if this light is on, it means that your engine cannot produce enough power to keep itself running. Turning off all non essential accessories will help increase the distance you will be able to travel with a poorly charged battery. Keep in mind that issues with the battery can also cause the light to come on so if the battery is old, it should be tested as well.

It is better that you have a certified technician inspect and test your charging system to diagnose the problem in order to minimize any chance of permanent damage to your car.

Is it safe to drive with the alternator warning light on?

When this light is illuminated, your car is still somewhat safe to drive as you will have enough battery power to run the engine. However, it is still dangerous to continue driving for long distances or at high speeds as the battery will run out of juice and the car will be harder to stop without the assistance of the engine. If you are on the freeway and this light comes on, you should pull off the freeway and move to lower speed areas as soon as possible.

As always, our certified technicians are available to come to you to help you diagnose any issues with your car’s battery.


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Chris

21 years of experience
1861 reviews
Chris
21 years of experience
Mini Cooper Clubman - Brake Pads Replacement (Rear) - Silverado, California
He arrived early, went straight to work, and it should have been quoted higher as it’s a Mini which takes longer than the average break job. He didn’t try to get more than the quoted amount. He even set out to replace a running light for me when he was finished. I thought there would hard sales telling me I needed more work but there wasn’t. Because he didn’t try to sell me more work, I will use him again. When I hired a mechanic I don’t want a salesman. 
Land Rover Range Rover Sport - Brake Pads Replacement (Front) - Irvine, California
Chris again has provided great Service. Everything was great. I was very happy with the work and will definitely have him return for any other work.

Bryant

11 years of experience
408 reviews
Bryant
11 years of experience
Ford Fusion - Brake Pads Replacement (Front, Rear) - Indianapolis, Indiana
Bryant has done great work on my car before, the latest work is no exception. He's very flexible, and goes the extra mile to get you back on the road.
Scion iA - Brake Pads Replacement (Front) - Carmel, Indiana
This is my first time using this service. I am very happy with it. Bryant was very knowledgeable and did quality work. I will use this service more regularly.

Edmar

21 years of experience
184 reviews
Edmar
21 years of experience
Chrysler 200 - Brake Pads Replacement (Rear) - Euless, Texas
Edmar always does a very good job. He's done a few different things on my car the last two years. Each job was performed very fast and top quality. Thank you once again.

Mazyar

7 years of experience
255 reviews
Mazyar
7 years of experience
Jaguar XF - Brake Pads Replacement (Rear) - Lawrenceville, Georgia
He was early, courtesy and actually helped me save some money since i didn't need all the work that i thought i needed done. Honest guy. Very knowledgeable. Great attitude.

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