Turn the key and the car doesn’t start? You may be tempted to blame the battery but it could also be your alternator. Always check your battery first, turn the key switch to the on position and see if any dashboard lights come on. If the lights come on, on the dashboard, and your headlights are dim, the battery may be just low and needs a charge. Next, open your hood and check you’re the connections on your battery, if there is excessive buildup on the terminals, you will need to clean those. First, disconnect the battery cables then clean your battery based upon the manufacturer’s recommendations.
Next, grab a pair of jumper cables and a friend with a running car, let the cables stay connected between both cars for 5 to 10 minutes then disconnect the cables and try to start the engine. If the engine starts, you have a dying battery. If it doesn’t start, the battery is dead and will need to be replaced. But, this could also mean the alternator is failing. If you’re a DIY expert like most NAPA Know How customers are, use a multimeter to check the charge of the alternator, if it’s between 13 and 15 volts, the alternator is in good condition, if it’s below, 13 volts, you’ll need to replace the alternator.