Is it possible for an alternator to work intermittently?

Catastrophic failures are usually due to an alternator malfunction, but can also be caused by a faulty drive belt or blown fuse. A related alternator failure is the battery warning light illuminating on a random or intermittent basis because the alternator's carbon brushes are sticking in their holders or are worn out.

Can an alternator go bad intermittently?

When your alternator begins to fail it can cause a variety of different electrical problems in your car, and eventually cause a breakdown. Alternators can go bad suddenly, or slowly over time.

Can a bad alternator work sometimes?

A faulty or dying alternator may only work in fits and starts. As a result, the alternator may not have what it takes to keep your battery fully charged — even with your engine running. As a result, you may find your car stalling out at odd times.

Can a voltage regulator work intermittently?

If your voltage regulator is operating intermittently, the electrical components around your vehicle will operate that way too. Whether it's your radio, dashboard lights, or more critical components like your fuel pump, you'll notice inconsistent operation.

Do alternators fluctuate?

If you get a voltage reading, it means one or more diodes are leaking and the alternator needs to be replaced. Leaking or shorted diodes can often cause a visible fluctuation in the output voltage of the charging system.

Intermittent Alternator Issue

What would cause alternator to fluctuate?

Fluctuating battery voltage can be caused by a bad connection or a problem with the alternator. Start by cleaning the battery terminals and cables of corrosion and deposits, and then directly measure the voltage across the battery when the car is running.

What causes alternator to undercharge?

In most cases of undercharging, the alternator may have an incorrect diameter pulley installed, the drive belt may be slipping or the alternator itself might be undercapacity for the vehicle application.

Why does my alternator only work sometimes?

Catastrophic failures are usually due to an alternator malfunction, but can also be caused by a faulty drive belt or blown fuse. A related alternator failure is the battery warning light illuminating on a random or intermittent basis because the alternator's carbon brushes are sticking in their holders or are worn out.

How do I know if my alternator or voltage regulator is bad?

Probably, the most common symptom associated with a bad regulator is flickering, dimming, or pulsing lights. To be more specific, you may notice that the vehicle's: Headlights fluctuate between bright and dim, without you doing anything. High beam isn't working as expected.

What are the symptoms of a faulty regulator rectifier?

Key Signs to Look For

You won't have any trouble diagnosing the faulty regulator rectifier if the battery is the cause. You'll note signs right away like poor starts, fluctuating meter readings, and dimmed headlights. around 13 volts, the bike will start to drain the battery.

What are the signs of a bad alternator?

How do you tell if it's the battery or alternator?

If the engine starts but dies immediately, your alternator probably isn't keeping your battery charged. If a jump starts and keeps your car running, but the car can't start again off of its own power, a dead battery is probably your answer.

Will a failing alternator throw a code?

HOW TO DIAGNOSE A FAILING ALTERNATOR. If you have a “Check Engine" light on, connect a code reader to the diagnostic port. If you find code P0562, you very likely have a failing alternator (note that codes may vary by vehicle make/model/year). Get it checked out before it fails entirely.

Can an alternator go bad without warning?

Often, the alternator can go out with little or no warning. But there are a few signs that will let you know it is about ready to die: The dash warning light ("ALT" or "GEN") illuminates. The lights are dimmer than usual and may pulsate from dim to bright.

How long will a car run with a bad alternator?

However, for most vehicles, expect as much as two hours of run time and as little as five minutes. Based on the speed at which you are traveling, this could be as little as a few miles or up to 100 miles away, if you are lucky!

What happens if the voltage regulator goes bad?

A bad voltage regulator can even affect your car's engine. For example, as this car part stops working properly, you might notice your car's engine sputters or stalls once in a while. It might also have trouble accelerating as you drive.

Does an alternator charge at idle?

Assuming the alternator, engine, belt, and battery are all in working order, then yes, a car battery will charge when idling. The only caveat is that it doesn't really “charge” that fast. This is solely due to the fact that the engine doesn't have a load on it when your car is simply idling.

What kills an alternator?

Running in full charge mode continuously can kill an alternator, so trying to have your new alternator try and charge your dead battery can result in immediate alternator failure.

Does a bad battery cause an alternator to overcharge?

The battery won't overcharge on its own – the overcharge is caused by the alternator's faulty voltage regulator.

What is a symptom your customer might find when the alternator is undercharging?

Symptoms of an undercharging or no-output alternator are usually pretty obvious: You see a message or warning light, such as a battery light on your dashboard, indicating an issue with the charging system.