4 Signs of a Bad Alternator

November 18,2016

Is it a bad alternator? This is a common question we get asked at the auto shop. In this article we hope to shed some light on the mechanics behind your car’s alternator, and include 4 key indicators that you’ve got a bad one. Below is a descriptive video of how an alternator works. In short, using a system of rotating coils, your alternator generates electricity for your vehicle’s entire system to run properly. Without it, your car wouldn’t even be able to start. But how can you tell if your vehicle’s alternator might be bad, before you’re having it towed to the shop? Here are the signs:

1. Are your lights dimming?

Because the alternator is integral to your vehicle’s electrical system, a case of dimming headlights or dashboard lights might be a more obvious sign of alternator failure. Other features that depend on the electrical system might start to waiver too, such as power windows/ automatic seats.

2. Are you experiencing things you can’t see, like odd smells or unusual noises?

The belts that the alternator works with and uses to run your car’s electrical system could be part of the problem here. Too much friction can occur if a belt is not turning freely or properly, and the belt can heat up, creating a burning scent. On the other hand, worn out or broken bearings can cause disturbing noises when running your vehicle, such as grinding and whining noises.

3. Is your battery causing you trouble?

The problem also might present as your alternator, but might actually be much simpler: a bad battery. Batteries for vehicles, just like all other forms of batteries, don’t last forever- so it’s crucial you determine if that is the issue, as your car can’t run without a reliable battery.

4. Is the warning light on?

Anymore, most vehicles on the road will have warning lights that let you know when something is wrong, and a “bad alternator” light is no exception. The light itself varies from vehicle to vehicle, though, and may present as an image of a battery, or as the letters ALT or GEN. Although these lights are helpful, they won’t always turn on right when there’s a problem, so it’s best to either do a self-check or take your vehicle to a mechanic.


In most cases, you can easily check your own vehicle for some basic issues, such as belts that are too loose or too tight, belts that are cracked, or a battery that is old or corroded. These are easier to deal with than a bad alternator, and checking to see that the alternator is not the issue can relieve some of your stress over the matter. 

If you’re still thinking a bad alternator might be your issue, call a Veenstra repair specialist at 616.454.6597. We’ll set you up with one of our thorough 22- point inspections to get to the root of your car’s problem, so you can get back on the road. Also, did you know that we offer complimentary services such as pickup and drop off? Read about it here!