If Your Car Won't Start, Is It the Ignition Switch or the Starter?

There is nothing more frustrating than settling into your car one morning and finding that it won't start. The first thing to check in these situations is the battery. If the battery is OK, then you have either a bad starter or a bad ignition switch. With a little bit of time and some patience, you can tell which one is the problem.

What Else Is Working?

Once you've established that your battery is fully charged, the next thing to do is to check your horn, headlights, interior lights, door locks, and four-way flashers. Next check to see if the radio, the wipers, and the turn signals work. Can you hear the fuel pump switch on when you turn the key? Do the lights inside and out dim if you try to crank the car? Note what works and what doesn't and then move on to the next steps.

Test the Starter

To figure out why your car won't start, it helps to know the difference between the starter and the ignition switch. The starter is an electric motor that cranks the engine, effectively starting the car. It is under the hood, usually on the passenger side at the bottom of the motor next to the transmission.

The ignition switch is a set of electrical contacts that activates the starter and usually is located on the steering column. The ignition switch activates the main electrical systems in your car. So if your radio, trip computer, wipers, and turn signals don't work and the fuel pump is dead, you're likely to have a bad ignition switch.

First, check the starter by turning the key in the ignition to ON and then using a circuit tester or voltmeter to see if there is power to the wires leading to the starter. If there is power, you have a bad starter.

Test the Ignition Switch

With the key in the RUN or ACC position, see if you are getting power to fuses 5, 8, 10, and 14. If you aren't getting power there, check fuse 18 and see if it's good.

If it's good, then check for power at pin 1 (red), 7 (red), 3 (pink/black) and 2 (gray/dark blue). If they check out, check for power at pin 8 (black/white) in the ACC position and 10 (yellow), 9 (dark blue), and 8 (black/white) in the RUN position. If you do not have power to these pins, the ignition switch is bad and will need to be replaced.

If you can narrow down the options that would explain why you can't start the car, even if you don't plan to make the repairs yourself, you will be better prepared to discuss it at the shop with a mechanic.

Sources

• "Troubleshooting a Car That Won't Start." Dummies.com.
• "What to Do When Your Car Won't Start." Confused.com.