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My Car Won’t Start: Is it the Starter, Alternator, or Battery?

why my car won't startUsually, when your car doesn’t start right up, you may immediately suspect that the battery has died. This isn’t necessarily true considering there are several different parts that are involved in starting your vehicle. To help you determine whether the starter, alternator or indeed the battery are at fault, let’s take a look at each of their roles and what could occur to indicate which element has failed.


The starter is exactly what it sounds like, in that it starts the car. It’s an electric motor with a Bendix gear mounted on the side of the engine. The Bendix gear is an engagement mechanism that allows the pinion gear to engage or disengage the flywheel of the engine, routinely when the starter is powered or when the engine fires. Electric motors and repeated engagement of the gears eventually wear out.


A vehicle’s battery turns over the starter to help engage the vehicle, converting chemical energy into the electrical energy necessary to power your car. However, it also acts as a surge protector in newer vehicles, stabilizing the energy supply in order to keep your engine running and protect the car’s computer from experiencing the harmful effects of a power surge. Your car’s battery is designed to be drained of amps only partially. It must then be refilled by the alternator. Batteries that contain leaded acid, such as marine batteries, are designed to be drained entirely and then refilled.


The alternator’s first task is to maintain the battery’s charge and will recharge the battery after the initial start. It also provides power that operates the car. Contrary to popular belief, nothing is run by the battery. The alternator generates the electricity for all electrical components, including the ignition, computer, power windows and locks, interior and exterior lights, as well as the radio.

Reasons Your Car May Not Start

To determine why your car isn’t starting, begin first by testing your battery. If the reading indicates the battery is:

    • Fully Charged
      • Test the starter utilizing an amp gauge. The starter will draw a charge from the battery. If it’s drawing too much, that’s a clear indicator that’s has failed. The vehicle may still start; however, it will continue to draw too much power and will drain the battery.
    • Low
      • The starter cannot be tested as it won’t have enough amps to run. If you crank the engine to test the starter and have no turnover, it could be one of three things including the battery, ignition switch, or starter.
    • No Charge
      • If the battery tester indicates there is little to no charge, allow the battery to charge and test again. A second reading will help determine if the battery is the cause of the no start.

Other Starting Issues

The battery may not have gone out entirely, but you may notice something is amiss because of a sound or a slow start. If you hear a clicking sound or other unidentifiable noises, it could be the starter solenoid indicating the battery is under duress. While you’re placing your key in the ignition or pressing the push-to-start button, your car’s computer is running a series of self-checks. If your car turns over hesitantly, the computer knows something is wrong with either the battery or the starter. However, if it doesn’t start up quickly enough, it could be the ignition.

Proceed With Caution

In the past, if your battery was dead it was easy to ask another motorist to assist by jumping your battery allowing you to get to a service station to purchase a new one. These days, it’s best to contact a professional such as a roadside assistance company or service center as opposed to jumping your battery yourself. Jump starting your vehicle, if not done correctly, can actually cause a surge in power which could damage electrical components, including the main computer.

The next time you notice your car is struggling to start up, you can be confident in knowing ahead of time if the battery, alternator, or starter are at fault. Batteries can die at any time but knowing the symptoms of what your car is exhibiting can help you prepare before you’re left stranded. Don’t wait until your battery, alternator, or starter goes out before taking your car to a professional to determine why your car won’t start.

At Sun Auto Service, we understand that you lead a busy life and having the start-up or battery issues never come at a convenient time. That’s why we offer battery testing at no charge for Nevada and Texas drivers—no appointment necessary! If you suspect your battery’s charge is low or believe your alternator or starter need further inspection, we can check that for you, too. If it’s determined that your vehicle does require a new battery, our technicians will replace it for you and have you back on the road in no time. Plus, you’ll be awed by our 5-year battery replacement warranty. With over 40 years in family-owned business, you can be confident in knowing your vehicle will be properly cared for by the professionals at Sun Auto Service.