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How To Diagnose A Failing Battery

Your VW car battery is something that many people take for granted until it starts to fail. While it works just like the batteries you use in a flashlight or small electronic device, it plays an important role in your car's electrical system. Fortunately, it's also an easy part to troubleshoot on your VW, and even replace yourself. 

In this post we will look at the following:

  • How car batteries work
  • How to diagnose a failing battery
  • Options for replacing a failing battery  

How Car Batteries Work

VW battery

A car battery stores electricity for your car. This electricity is used to power things like the lights, radio, and other equipment like windshield wipers or climate control. Most importantly, the battery is used to start your car. When you turn your ignition key, it activates the car's starter motor, which is powered by the battery. 

After your car starts, an accessory belt spins the car's alternator. The alternator then produces electricity for the car to run, and keep the battery charged.

How to Diagnose a Failing Battery

The easiest way to diagnose a failing battery is to check its age. Car batteries last an average of three to five years depending on the quality of the battery and the temperatures it operates in. If your battery is three years old or older, it's a good idea to replace it, even if doesn't show any signs of failing. This preventive maintenance will keep you from getting stranded with a car that won't start.

If your battery starts to fail it could happen slowly or all at once. The most obvious sign is that nothing happens when you turn your VW's ignition key. However, there could be other signs including:

  • The car is slow to start or the starter motor turns slowly.
  • The starter makes a clicking noise or you hear a click instead of the starter engaging
  • The headlights are dim
  • The car's interior lights are dim and go out completely when you try to start the car

Another way to diagnose a failing battery is to test it with a battery tester or multimeter. To do this:

  • First, put on protective gear including eye protection
  • Make sure the car and all of its electrical systems are off
  • Touch the battery tester's positive connector to the battery's positive terminal marked '+'
  • Touch the battery tester's negative connector to the battery's negative terminal, marked '-'

If the battery tester reads less than 12 volts, it's a sign the battery is weak and is likely failing. 

For more information on why batteries fail, check out this page.

Options for Replacing a Failing Battery 

OEM vw battery

The best options for replacing your car battery are to take it to a mechanic or do it yourself. As for the battery, the best option is to replace it with an OEM VW battery. OEM VW batteries are optimized to meet VW standards for performance and made to last as long as the original manufacturer's warranty. And VW Parts Vortex can help you find the right battery for your car. We can even show you how to replace it and reset your VW's engine immobilizer

As with all of the VW parts we carry, we have a no-hassle return policy and will do free parts lookups for you. Call or order online today!