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It must have happened to you before: you got in your car, turned the ignition key and nothing happened. If this has never happened to you, it will probably happen. It can be useful to be able to diagnose yourself, because then you know if it is a battery problem, or a broken starter motor, or the starter relay (also called a solenoid). If you do this yourself, you can save a lot of money at the garage. Testing an empty battery is not difficult, but in order to test the starter relay properly, you need to know a few things first. In addition, you must be sure that the problem is not elsewhere: the battery, the ignition lock or the starter motor. If you have access to some simple tools, you can make a good diagnosis by following the instructions in this article.
To step
Position the car so that you can easily reach the starter solenoid.- You may only be able to reach the starter solenoid from below, but that depends on the type of car. If you must, always use proper car mounts and follow all safety precautions. You may have to remove some things next to the car to make room for it to work.
- You may only be able to reach the starter solenoid from below, but that depends on the type of car. If you must, always use proper car mounts and follow all safety precautions. You may have to remove some things next to the car to make room for it to work.
Locate the electrical connectors on the starter solenoid. One of the poles has a braided wire that is connected to the starter motor. This is the positive pole. - Check that your starter relay is getting the correct voltage by holding a voltmeter against the positive pole of the starter relay.
- Hold the positive lead of the voltmeter against the positive terminal of the relay and connect the negative lead to ground. Ask a friend to start the car. When he or she turns the key, the voltage should be 12 volts.
- If the voltmeter shows less than 12 volts, the problem is with the battery or the ignition switch. The starter relay should also make a "click" sound. But beware, the starter relay can also make a clicking noise while the voltage is below 12 volts, so it is important to use a voltmeter to test the starter relay.
- Hold the positive lead of the voltmeter against the positive terminal of the relay and connect the negative lead to ground. Ask a friend to start the car. When he or she turns the key, the voltage should be 12 volts.
Test a starter relay by applying power directly from the battery.- From the starter solenoid, remove the wire leading to the ignition switch and short by connecting the two poles of the starter solenoid with an insulated screwdriver. Now you give the starter relay 12 volts, directly from the battery. The starter relay should now be activated and the starter motor will start the car. If the ignition switch is not providing enough power, or if the starter solenoid is old and stuck, this test may reveal the problem.
- From the starter solenoid, remove the wire leading to the ignition switch and short by connecting the two poles of the starter solenoid with an insulated screwdriver. Now you give the starter relay 12 volts, directly from the battery. The starter relay should now be activated and the starter motor will start the car. If the ignition switch is not providing enough power, or if the starter solenoid is old and stuck, this test may reveal the problem.
Tips
- If the starter solenoid is not working properly, or if you don't know if the problem is with the starter solenoid or starter motor, consider replacing the entire starter motor rather than just the starter solenoid. The costs are not much higher and technicians often recommend that because the parts work closely together.
- Test the battery first. Then the ignition switch and the starter motor before testing the starter relay.
Warnings
- Make sure that the parking brake is always on and that the car is in neutral.
