How to Tell If Your Alternator is Failing (And What to Do About It)
Your car’s alternator is the unsung hero of your vehicle’s electrical system. It keeps your battery charged, powers your headlights, radio, and electronics, and ensures everything under the hood runs smoothly. But when it starts to fail, it can lead to frustrating issues—or worse, leave you stranded with a dead battery.
At All-Star Automotive Repair in Columbia, MO, we’ve helped countless drivers catch alternator problems early. Here’s how to tell if your alternator is failing—and what steps to take before it turns into a costly breakdown.
What Does an Alternator Do?
The alternator generates electrical power and charges your car’s battery while the engine is running. Without it, your battery would drain quickly, and your vehicle wouldn’t be able to function.
It’s a key part of your car’s electrical system, and when it starts to go bad, you’ll notice signs in several areas.
6 Common Signs Your Alternator Might Be Failing
1. Dimming or Flickering Lights
If your headlights or dashboard lights are dim or flickering, especially when idling, it could mean your alternator isn’t generating enough power.
2. Dead Battery (Again and Again)
A weak alternator can’t charge your battery properly. If you’ve recently replaced your battery but it keeps dying, the alternator could be the real issue.
3. Electrical Issues
Malfunctions in your radio, power windows, heated seats, or dashboard instruments can be a clue. These components depend on steady power from the alternator.
4. Strange Noises Under the Hood
A failing alternator may produce a grinding or whining sound due to a worn bearing or damaged internal components.
5. Battery Warning Light or Dashboard Alerts
Your dashboard’s battery icon might light up when the alternator is underperforming. This warning is often misunderstood—it doesn’t always mean the battery is bad!
6. Engine Stalling or Trouble Starting
Since the alternator powers key engine components, a failing one can cause your car to stall or struggle to start, even if the battery seems fine.
How to Confirm It’s the Alternator (and Not the Battery)
Battery and alternator issues often get confused, but there are a few key ways to tell them apart:
Symptom Battery Problem? Alternator Problem?
Car won’t start after sitting overnight ✓ ✖
Car dies while driving ✖ ✓
Dim lights at low speeds ✖ ✓
Needs frequent jump-starts ✓ ✓ (if alternator isn’t charging battery)
Pro Tip: A quick diagnostic test at All-Star can confirm whether it’s your alternator, battery, or both.
What to Do If You Think Your Alternator Is Failing
If you’re experiencing any of the above symptoms, don’t wait. Driving with a failing alternator can leave you stranded and cause further damage to your battery and electrical system.
Step 1: Schedule a Charging System Diagnostic
Our team at All-Star Automotive Repair can run a complete electrical system test to identify whether the alternator is the culprit.
Step 2: Replace the Alternator (if needed)
If the alternator is worn out or damaged, replacing it will restore reliable power to your vehicle. We’ll walk you through your options and get you back on the road quickly.
Step 3: Check the Battery & Belt
Sometimes, alternator issues are tied to a bad serpentine belt or a weak battery. We’ll inspect everything and make sure your car’s electrical system is in top shape.
Don’t Get Stuck With a Dead Battery — Get It Checked Today
If you’re noticing dim lights, starting trouble, or dashboard warnings, it could be your alternator. Catching the issue early can save you time, money, and the headache of being stranded.
All-Star Automotive in Columbia, MO offers fast, accurate alternator diagnostics and repair. Let our experienced team keep your car’s power flowing strong.
Schedule your charging system check today!
