How To Diagnose A Failing Alternator

The alternator does an important job in your vehicle. It turns mechanical energy from the engine into electricity. The alternator then powers everything from your headlights to your radio. It also charges your battery, which starts the car. But what happens when your alternator doesn’t work right? Let’s explore some common alternator problems and how to spot them.

Flickering Or Dim Lights

The first sign of an alternator issue could be your vehicle’s lights. The alternator powers the headlights and accessory lights in your car. (Learn more about some common alternator problems here.) When the alternator fails to generate enough power, the electrical load of the vehicle exceeds the supply, resulting in lights that appear weaker than usual or flicker.

This can happen to your headlights, dashboard lights, or other interior lights. If you notice changes in your lights while driving, it’s worth checking your alternator. You may want to check for a faulty voltage regulator or worn-out brushes within the alternator. The simplest way to do this is to measure the voltage coming from the alternator when the engine is running.

Warning Lights And Strange Noises

Your car dashboard has a light for the alternator. It may display as “ALT”, “GEN” or a battery symbol. If this light comes on, it’s a clear sign there could be an alternator problem.

Another indicator your alternator is failing is strange noises. This happens because parts inside the alternator could be wearing out. If you hear a growling or whining noise that changes with engine speed, it’s time to investigate.

Battery Problems

Remember, one of the main functions of the alternator is to charge your battery. If the alternator isn’t working right, your battery will drain quickly. You may find your car struggling to start or not starting at all. This can seem like a battery or starter issue, but if the battery is new or in good condition, the problem is most likely the alternator.

Preventative Measures

It’s good to recognize alternator issues early because a completely failed alternator can leave you stranded. There are a few preventative steps you can take to help avoid alternator problems:

  • Proper Belt Tension: Take a moment to get under the hood and check your belts. Keeping the drive belt and tensioner in good condition is crucial. An overly tight belt can quickly wear out the alternator bearings, and a loose belt is also detrimental.
  • Check Wiring: Regularly inspect the wiring connections between the alternator, regulator, and battery. Look for any signs of damage, disconnection, or corrosion.
  • Diagnose Early, Address Promptly: If you notice the signs of a low voltage output from your alternator, combined with strange noises or belt sounds, investigate asap.

Find Your OEM Alternator At Tom’s Foreign Auto Parts

Keep an eye out for these symptoms – and be sure you seek a reliable replacement part if your alternator is going bad. Tom’s Foreign Auto Parts specializes in the highest quality recycled OEM auto parts, including alternators, for ToyotaBMW, and many other popular makes and models.

We’ve been in the auto parts business for over 30 years and are a reliable and trusted auto recycler. You can save up to 75% off OEM prices on thousands of auto parts when you shop online with us.

Have questions about finding an alternator for your vehicle? Contact us online or browse parts by make here. If you’ve diagnosed the problem and find yourself in need of a new alternator, start your search for a high-quality OEM replacement at Tom’s Foreign Auto Parts today.