Car Won’t Start? It Might Not Be the Battery

If you tried a jump-start and your car won’t start, you’re looking at a problem bigger than the car battery. (If it is the car battery, you might have noticed some of these six subtle signs you have a bad battery.)

First, don’t keep testing the ignition. You could overheat your starter if you don’t already have a bad one.

Interstate Batteries automotive electronics expert Jeff Barron took a few moments out of our battery testing lab in Dallas to talk through the most common reasons why your car won’t start.

“Engines need fuel, spark and air in order to run. You take one of these away, and it will not start,” Barron said. “Engines are essentially a huge air pump with the air intake coming from outside and running through a set of sensors allowing the correct mixture to make it run efficiently.”

Any number of failed parts can make your car stall. In fact, a fresh, healthy battery can mask some starting problems.

If your car won’t start but has some power …

You may have a blown fuse if the car makes no noise at all and only some electronics work. Don’t keep trying the engine and don’t try jumping it. Instead, examine its fuse box. You may be able to spot an obviously blown fuse or you may need to test them with a multimeter or a voltmeter. Fuses are inexpensive and, depending on the make and model of your car, not too difficult to replace.

Heads up: Something else caused the fuse to blow. What might have drawn so much power through that circuit in the first place? Is it the fuse for the ignition switch, the fuel pump, the engine control module or any other vital part? The only way to know is to get a proper engine diagnostic at your trusted repair shop.

Also, check the battery connections. It might not be the fuse or ignition switch; it could be that your battery cables somehow came loose. You might be able to simply tighten the bolts on the battery clamps and then the car will start right up. How might battery clamps come loose? One culprit could be corrosion, so be sure to clean corrosion off your battery and to make sure your car always gets a strong start.

If your car won’t start and the electronics fade out …

You might have a bad alternator or ignition switch — but you can still jump-start it. Now, the dashboard lights might fade out or some of the accessories might not turn on correctly because of either of these. (This may also be a common sign that your battery is nearly dead.)

Now, it’s probably the ignition switch if the car starts and then suddenly stalls. A failed ignition switch can turn on the car, only to cut power to the fuel system, which shuts the car off. Ignition switches can also kick off a host of other troubling issues, such as stalling while you drive or your car key getting stuck.

If the car starts and as you’re driving, you notice the dashboard lights or headlights brighten or weaken depending on the RPM, that’s the alternator. (And you’ll likely need to replace the car battery with it.) Once you have the car running, you can check the charging voltage: It should be greater than 13.1 volts (between 14-15 volts, usually.) Anything less than that while the engine’s running, and you know you’ve got a bad alternator. Get to a repair shop as soon as you can.

If your car makes clicking noises …

You may have a bad starter if the car won’t start, but the battery is good.

Clicking noises usually point to an electrical problem. The clicking is the sound of the starter motor spinning. The starter is trying to make the electrical contact to turn the engine over — and either the car battery or the starter itself is too weak. One loud click means the starter’s not getting enough power. Rapid clicking means the starter’s getting power but that power’s not going to the engine.

That means if you hear rapid clicking instead of that reassuring vroom when you try to jump a car, it could be the starter. Don’t keep trying the key or you really will blow out the starter.

If your engine makes a strained, whirring noise …

You may have a bad engine control module, body control module or power control module. Even if you jump the car, you hear the switch, the click of the starter, the turn of the engine — and no start.

If you keep pressing the ignition, the engine will keep whirring. Don’t do that. You may burn out the starter. Starters aren’t designed to run for more than 30 seconds at a time, as in, just enough time to get the actual engine running.

These control modules manage the fuel, air and spark the engines need to get going. If one of them is out of commission, not even a jump will get you going. That’s when you need a repair pro with tools and parts to get your car starting again.

If your car won’t start and the engine sputters briefly …

You may be out of gas or have a bad fuel pump if you’re trying to jump your car and it still won’t start. That sputtering noise will be brief. That’s the engine burning up a few drops and sucking in too much air for the fuel mixture.

If it’s out of gas, you have a straightforward fix. Hitch a ride to your nearest gas station for a gas can and a gallon of your car’s favorite beverage.

If it’s the fuel pump, get to a professional repair shop for help.

You might have a dead battery if …

• If your dashboard lights turn on and start to fade (or if they don’t turn on at all)
• If your car’s clock resets to 12:00 or the electronics forgot your Bluetooth settings
• If it is especially cold outside when your car won’t start.
• If you jump your car and everything works fine after you drive it at highway speeds for quite a while
• If you test your 12V car battery and see anything less than 12.6 to 12.8 volts.

Now, a dead battery can be a symptom of a dying alternator or a deeper electrical issue, including broken cables somewhere along the line. As long as you regularly get a battery test with every oil change, you’ll stay ahead of any battery-related problems.