Starting Problems? How to Tell If It’s the Battery or Alternator

Nothing is worse than getting into your gas- or diesel-powered car or truck, hitting the ignition and going nowhere. Sometimes the issue can be the battery. On the other hand, a failing car alternator will cause your vehicle to shut off soon after you get it started because it’s not recharging the battery. Here are the signs and symptoms of a bad battery or car alternator and how to determine which one is causing issues.

Technician checking a car battery

Signs & Symptoms of a Bad Battery

There are some telltale signs of a bad battery. Look for these issues when your car is hard to start, starts inconsistently, or there’s no sound or light on when you hit the ignition.

  • Dashboard and interior lights are dim
  • Windshield wipers are slow or barely move at all
  • Electric windows slowly open or close
  • Battery and/or cables are corroded
  • Radio won’t turn on
  • Swollen battery

You could have a bad battery if the cranking of the engine is sluggish, there’s no sound or interior lights when you try to start the vehicle, your car starts inconsistently, or you can start it with jumper cables but the vehicle will not start again after being shut off. A loose or corroded connection can also cause issues. Not sure? Get to Les Schwab and our pros will take a look and share some options.

How to Tell if Your Battery Is the Problem

If jump-starting works, then it’s probably your battery. The question then is, how old is that battery? If it has been starting your car or truck for more than four years, it could just be at the end of its lifespan. But a battery can also be drained when the lights are left on when the car isn’t running. The pros at Les Schwab have the tools needed to tell the difference and make recommendations.

Schedule A Free Battery Check
Schedule A Free Battery Check

Car stranded on the side of the road

Signs & Symptoms of a Bad Alternator

Gas and diesel-powered vehicles use an alternator to keep the battery charged and run all of the electric systems, such as your radio, windshield wipers and comfort controls. Essentially, the alternator is a small generator that creates electricity from a belt directly connected to the engine. As long as that alternator is creating electricity and the battery is good, your car should start and stay running. If the vehicle won’t crank or start but the headlights are still working, look to problems with the starter or other parts of the engine.

How to Tell if Your Alternator is the Problem

While it can be difficult to tell if your alternator is creating electricity without a lot of specialized tools, there are some signs to watch for:

  • Trouble starting the vehicle
  • Frequent stalling after you’ve started your vehicle
  • Squealing sound coming from the engine that gets louder when you use the heater or sound system (this may be your alternator bearings)
  • Interior and exterior headlights that seem to dim and brighten
  • Check-engine or battery indicator light illuminated on your dashboard
  • Vehicle immediately stops running after a jump start

Here’s a quick way to diagnose your alternator: Get the vehicle started (if possible). Then turn on your radio and tune to a low number on the AM dial. Finally, rev the engine. If you hear a whine or the sound goes fuzzy when you hit the gas, your alternator is probably failing.

Schedule A Free Battery Check
Schedule A Free Battery Check

Can You Drive with a Bad Alternator or Battery?

It is possible to drive with a bad alternator or battery. But you probably won’t get far. With a bad battery, you’ll be stuck the next time you go to start your car. A bad alternator will quickly deplete your car battery and could cause your vehicle to stall at any time. Even while you’re driving.

To avoid being stuck on the side of the road or someplace you don’t want to be, get a free battery and alternator inspection at Les Schwab. If it’s the battery, we’ll help you choose the right one for your vehicle. If it’s the alternator, we’ll make recommendations and help plan your next steps.

What’s the Purpose of Your Car Battery & Alternator

An auto battery supplies an initial electric charge that travels through the starting system on both gas and electric vehicles. Once a gas- or diesel-powered vehicle is running, an alternator sends current back to recharge the battery as you drive. It supplies power for your car’s electronics when you’re underway and makes sure the right amount of charge goes back to the battery.

Vehicle electrical system drawing

If Your Car Still Won’t Start, Stop by Les Schwab

Diagnosing battery and alternator issues isn’t always easy. If you’re experiencing any of these issues, get your vehicle to Les Schwab for a free inspection and some solid advice. Our trained technicians have the tools and experience to pinpoint the issue fast. That includes inspecting your battery fluid level, the posts (the terminals marked + and -) for corrosion, and cables for snug connections, as well as measuring the voltage and cold cranking amps (CCA) along with your alternator’s voltage and current output.

Schedule A Free Battery Check
Schedule A Free Battery Check