Starter motor and circuit in vehicle check

Go for it. With the battery and the starter eliminated, it's time to work your way through the car. The best place to begin is with the electrical system. However, before you go monkeying around with everything else, check your fuses to be sure it's not that simple.

Turn the key to the "On" position, not all the way to start, and check the following:. It can also affect any electrical component, especially those that, like the starter, are exposed to the elements.

If you have someone to help you, you can test the starter connection by holding a circuit tester lead on the wire that engages the starter. This is the smaller of the two wires connected to the starter.

What Goes Wrong?

Have a friend turn the key and check the current. If you're getting current to the starter but it isn't spinning, you will need to replace it. Note: Be sure that no part of your body is near the moving parts of the engine—it could still start at any time!

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If your starter spins freely when you turn the key, the problem lies elsewhere. Now you can begin to check the other systems that could keep it from firing up. With the starter-related causes of your problem out of the way, we continue the search for why your car won't start. If your vehicle is fuel injected, there are a number of subsystems that could be the culprit. It will take some serious diagnostic work to figure it out, but there are some things you can check in the garage in an attempt to narrow it down. These could save you some money and avoid a trip to the repair shop.

Each fuel injector has a connector on top. You should check every electrical connection you can find under the hood to be sure it's tight.

Checking a starter circuit

The items above are things you can easily check yourself using everyday automotive tools. There are many other elements of your fuel injection system that require electronic diagnosis. Unless you are familiar with this and have the right equipment, it is best to leave this to the pros. With the major systems checked out, there are a number of other things you can check to see why your car won't start.

Table of Contents Expand. Dead Battery. Dirty Cables. Bad Starter. Further Troubleshooting. Electrical No-Start Problems. Ignition System Troubleshooting. Fuel System Troubleshooting. Matthew Wright has been a freelance writer and editor for over 10 years and an automotive repair professional for three decades specializing in European vintage vehicles. Updated September 07, If the red warning lights do light up, turn the key to the start position. In most cars, the dash warning lights should turn off at this key position. If you're not sure, turn on the headlights.

When you try to start the car, the lights should either dim considerably or turn off completely. If they do, your ignition switch should be good. If not, the switch will need to be replaced. If you don't have a multimeter, there is an easier test you can perform using simple hand tools.

When does the starter motor need to be replaced?

Test your coil and, if it's bad, replace it. Remove your distributor cap and check the inside for moisture. If there is even a drop or mist of water inside, wipe it out with a clean, dry cloth. Inspect the cap for cracks and replace it if necessary. Once it's dry, it should work. These are all signs the battery is down on charge. Load test the battery to confirm its condition which can be done using and observing the headlights of the car and by watching the video below. If the battery warning light is not on while driving this means the battery is probably being charged properly and it has lost its ability to hold a proper charge.

Starter solenoid

Avoid trying to crank the engine over when anyone is near the battery. A battery is sometimes filled with explosive gasses that can ignite when extreme heat or a spark is present. If the battery tests bad and the battery light has not been on then the battery needs to be replaced.


Residual battery acid around the top of the battery can be present so wear gloves and avoid touching your clothes or skin when working on or near the battery. If needed use baking soda and a garden hose to neutralize any acid residue before you begin replacement. If the battery fails its load test it will need to be replaced with a new or good used battery of comparable size and cranking amps. You can get an Optima or AC Delco replacement battery which last longer but cost a little more online from sites like Amazon which you can get through prime in one day or just head on down to your local parts store for a replacement.

Record radio preset stations for re-entry before removing the battery.

Here is a video on how to replace your battery. If in the dash the battery warning light has been on prior to this repair and the battery is fairly new then the battery will need to be jumped to get the engine running so the alternator can be checked. Jump the battery using jumper cables which you can purchase online from sites like Amazon. Be careful not to connect the jumper cables backwards by connecting the negative to the positive battery terminal or you can cause electrical system damage.

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This step is necessary to test the alternator which will be in the next video. Test the alternator voltage output once the engine is running. If the alternator fails this test then it will need to be replaced. The battery supplies voltage to the starter through positive and negative battery cables which need to be clean, tight and free from corrosion. If you know the battery is good because it is fairly new or you have tested it has passed there could be a battery connection problem at the terminals or starter motor itself.

Here are the symptoms of a bad connection.

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The battery cables are used to transfer the battery voltage to the engine starter and to the electrical system. These cables are subject to battery acid which can produce an internal cable failure. Corrosion and loose connections stop electrical current flow. When this condition occurs the car will act much like a low battery by not allowing the voltage to continue to the starter motor. Check both the negative and positive battery cables for abnormal bulging, weakness or corrosion.

This problem can be sometimes overlooked by most mechanics and can be intermitted. These conditions cause heat which will produce the power disconnect.

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When the connection cools it can start working again. Inspect the battery cable ends for corrosion which means they need to be cleaned. While wearing rubber or vinyl disposable gloves grasp both negative and positive battery cable ends and try to wiggle them to check for tightness. Then use a wrench or socket to loosen and remove the cable end. Be careful not to touch the wrench or ratchet to any metal parts or the opposing terminal to avoid a short circuit.

If the end is badly eaten away by acid you may need to use a pair of channel locks to work the cable end loose. Then replace the battery cable end which you can get from Amazon or the local parts store. Like most heavy electrical load components such as starter there is a fuse and relay to protect the circuit. These components are usually located in the fuse panel or power distribution center under the hood.

If the fuse fails it will cause the starter to not operate.