Signs of a Bad Alternator
Written by Lee Wyatt (last updated August 9, 2012)
The alternator is one of the most, if not the single most, important parts of the engine of a vehicle. Keeping it in good working order should therefore be one of the most important tasks that any driver should remember to do. The sad fact of the matter though is that most people don't really pay all that much attention to the alternator. If you ignore the signs of a bad alternator, you can easily find your car not going anywhere, and the battery you just bought could end up dying within a couple of days. To help ensure that this doesn't happen, keep in mind these common signs of a bad alternator.
- Belt. The alternator belt is one of the easiest things to check, and frankly one of the first things to go bad on the alternator. Checking the alternator belt to ensure it is in good working condition is amazingly easy, all you need to do is look at it and inspect to make sure that it doesn't look cracked or worn. In addition, you will want to run your hand over both sides of the belt to double check an make sure that there are no teeth missing either.
- Accessory lights. Believe it or not, but the accessory lights that are on your dashboard can be a sign of a bad alternator. The best way that these can show you that you might have a bad alternator is when you turn the accessory on. If they act slow, don't light up all the way like they should, or if the radio doesn't even play, then you should take a look at the alternator.
- Volt gauge. Most cars and trucks have a voltage gauge on the dashboard to help you keep an eye on how the battery is working. When the alternator isn't working properly, this gauge will be lower than it should, and can even jump around erratically. If you notice this happening, then you will want to have both your battery and the alternator checked out.
- Battery service light. A common light that can be found on many vehicles today is the battery service light. If there is a problem with the battery, whether it be electrical in nature, or it is draining too quickly, or whatever, this light will come on. When that happens you will need to check the battery, check the alternator, and check the wiring to ensure that the problem is taken care of.
- Check with a voltmeter. Another way to check to see if your alternator is working properly is to use a tool called a voltmeter. This tool will measure the voltage that is in a circuit, and will allow you to see whether the circuit is running properly. Typically, all you will need to do is turn the accessories in your car on, and then run the voltmeter over the battery. The reading should not go below 13 volts, and with the accessories off it should be between 14 and 14.4 volts. If it shows up as less than that, you have a problem and will need to replace the alternator.