Signs of a Failing Alternator & When to Get It Checked

Your vehicle’s alternator plays a crucial role in keeping everything running smoothly. It’s responsible for powering the electrical system while the engine is running and ensuring your battery stays charged. But here’s the catch—when an alternator starts to fail, it can mimic battery issues, leading to common misconceptions about what’s actually wrong with your car.

Understanding the early warning signs of a failing alternator can save you from unexpected breakdowns and costly repairs. So, how can you tell if your alternator is on its way out? Let’s break it down.

How Does an Alternator Work?

The alternator is like your car’s personal generator. It converts mechanical energy from the engine into electrical power. When your engine runs, the alternator generates electricity that powers essential components like headlights, dashboard lights, and even your radio.

Here’s a simple breakdown of how it works:

• The alternator is driven by the serpentine belt, which spins the alternator’s rotor.
• This spinning motion creates an electrical current, which is regulated by the voltage regulator to ensure a steady flow of electricity.
• The generated power is then used to charge the battery and run the vehicle’s electrical components.

Without a properly functioning alternator, your car’s electrical system will begin to fail, eventually leaving you stranded.

What Does an Alternator Do in a Car?

While many people assume the battery powers their car while driving, it’s actually the alternator doing most of the heavy lifting. Here’s what it takes care of:

• Powering the vehicle’s electrical system – This includes your headlights, dashboard lights, power windows, A/C, radio, and more.
• Keeping the battery charged – The battery primarily starts the engine, but once the car is running, the alternator keeps it charged so that it’s ready for the next start.
• Preventing electrical malfunctions – A bad alternator can cause flickering lights, weak radio signals, and even complete electrical failure, leading to dangerous driving conditions.

How Can You Tell If the Alternator Is Going Bad?

If your alternator is failing, your car will give you plenty of warning signs. Here are the most common symptoms:

• Dim or flickering headlights – If your lights get dim when you rev the engine or flicker randomly, your alternator might not be supplying enough power.
• Dashboard warning light – The battery warning light often indicates an alternator issue rather than a battery problem.
• Weird noises – A failing alternator can produce a grinding or whining noise due to worn-out bearings or internal component failure.
• Electrical issues – If your power windows, radio, or air conditioning start acting up, your alternator might not be delivering enough power.
• Frequent battery drain – A weak alternator will struggle to recharge the battery, causing it to die more often than usual.

If you notice any of these symptoms, it’s time to test your alternator before the situation worsens.

Signs of a Bad Alternator vs. Bad Battery

One of the biggest mistakes drivers make is assuming a dead battery means they need a new one. But before you rush out to buy a replacement, consider whether the alternator is the real culprit.

Here’s how to tell the difference:

• Jump-start test: If your car starts after a jump but dies soon after, your alternator is likely failing. If it stays running, the battery was probably the problem.
• Dim headlights when idling: If your lights brighten when you rev the engine, the alternator may not be supplying enough power.
• Battery vs. alternator failure symptoms: A failing battery usually results in a slow crank when starting the car, while a failing alternator causes electrical malfunctions even while driving.

If you replace the battery and the problem persists, it’s a strong indicator that your alternator needs attention.

Alternator Issue Symptoms: When to Take Action

Ignoring alternator issues can lead to major vehicle failures. Here are key warning signs that you should get your alternator checked immediately:

• Dim or flickering headlights and dashboard lights – A surefire sign of inconsistent power supply.
• Strange noises – Grinding, whining, or growling sounds can indicate internal alternator problems.
• Frequent battery drain – If you keep needing jump-starts, the alternator may not be doing its job.
• Electrical malfunctions – Power windows rolling up slowly, the radio cutting out, or A/C issues can point to an alternator failure.
• Burning smell – Overheating alternator components can produce a burning odor, which should never be ignored.

How Long Will a Battery Last with a Bad Alternator?

If your alternator dies completely, your battery will only last a short time—typically between 30 minutes to a couple of hours, depending on how many electrical systems you’re using.

Here’s what happens when your alternator stops working:

• The battery will take over, but it will drain quickly.
• As power diminishes, essential functions like headlights and power steering may fail.
• Eventually, your car will stall completely, leaving you stranded.

What to Do If Your Alternator Fails While Driving

If you suspect your alternator is failing while driving, take these emergency steps:

1. Turn off non-essential electrical components – Shut off the radio, A/C, and any unnecessary lights to conserve battery power.
2. Find a safe place to pull over – If you notice flickering lights or difficulty steering, pull over before the car stalls.
3. Call for roadside assistance – A bad alternator will prevent the car from restarting, so you’ll need a tow to Burt Brothers.

When to Get Your Alternator Checked or Replaced

If you notice symptoms of a failing alternator, don’t wait until you’re stuck on the side of the road. Here’s what you should do:

• Test it at home – Use a multimeter to check if your alternator is producing between 13.5-14.5 volts when the engine is running.
• Schedule a professional inspection – A mechanic at Burt Brothers can run a more thorough diagnostic test to confirm the issue.
• Consider the cost of repair vs. replacement – While some alternator components can be repaired, in many cases, a full replacement is more cost-effective.

Conclusion: Don’t Ignore Alternator Issues

Your alternator is one of the most important parts of your vehicle’s electrical system. If you’re noticing dim lights, electrical issues, or strange noises, don’t ignore the warning signs! Catching alternator problems early can prevent major breakdowns and costly repairs.

At Burt Brothers, we’ll make sure your alternator is in top shape, so you don’t get stuck on the road. Schedule your alternator inspection today and drive with confidence!