What is a Starter Solenoid?

A starter solenoid is an electrically operated switch that controls the starter motor of an engine. It closes the starter circuit when the ignition key is turned to the “start” position; it opens the circuit when the key is returned to the “run” position.

The starter solenoid is a relatively simple device, but it plays a vital role in starting your car. If you have any problems with your starter solenoid, it’s important to have it checked out by a qualified mechanic as soon as possible.

If one were to summarize the functions of a starter solenoid, it would be these three:

• It connects the battery to the starter motor when the ignition key is in the start position. During this connection, it also provides a high current to the starter motor.
• It is responsible for mechanically driving the pinion. This pinon is what meshes with the flywheel to turn over the engine.
• It acts as a switch. When you turn the key to the start position, it completes the circuit between the battery and the starter motor. Once you release the key, it breaks that circuit.

How Does a Starter Solenoid Work?

When the ignition switch is turned to the “start” position, current from the battery flows through a wire to the solenoid. This flow of current creates a magnetic field around the solenoid coil. The magnetic field pulls on a plunger connected to the starter switch.

When the key is turned back to the “run” position, the current to the solenoid is cut off, and the plunger is pulled back by a spring.

This action opens the starter switch and breaks the circuit between the battery and the starter motor. The starter motor then stops turning the engine over, and the car comes to a stop.

Where are Starter Solenoids Located?

Starter solenoids are typically located on or near the starter motor. In some cases, they may be mounted on the fender well or firewall.

It would only make sense that the starter solenoid would be located close to the starter motor, as it needs to be able to send power to the starter motor to start the engine.

In older cars, it was relatively easy to locate the starter solenoid. However, in newer cars, they can be more difficult to find as they are often hidden away in the engine bay.

In case you are wondering what a starter solenoid looks like. Well, you are looking for a cylindrical-shaped device that is usually black or silver. It will have a large wire going to the battery’s positive terminal and another large wire going to the starter motor.

If you’re unsure where your starter solenoid is located, consult your car’s owner’s manual or a qualified mechanic.

Bad Starter Solenoid Symptoms

Now that we know what a starter solenoid is and does let’s take a look at some of the symptoms that may indicate that yours is going bad.

1. Rapid Clicking Sound
2. Car Won’t Start or Intermittent Starting
3. Grinding Noises
4. Starter Remains Engaged

Let us dig deeper into each of these symptoms:

1. Rapid Clicking Sound:

If you turn the key to the “start” position and you hear a rapid clicking sound, your starter solenoid is likely going bad. This means that starter is spinning but not engaging.

A bad starter solenoid can produce a rapid clicking sound for several reasons. The most common reason is that the solenoid is not getting enough power to engage the starter. This can be caused by a problem with the battery, the starter circuit, or the solenoid itself.

If the clicking sound is accompanied by other symptoms, such as the engine not starting, it is likely that the issue is with the starter solenoid. Loose connections inside the starter solenoid usually cause this sound. When the contacts are loose, it can cause an electrical arc which results in the clicking sound you hear.

Though sometimes it is possible that you only hear a single click, which is normal. If you only hear a single click and the engine doesn’t turn over, it’s likely that your starter motor is bad and not your starter solenoid.

If you hear multiple clicks, it’s worth checking the connections between the battery and starter solenoid to see if they are loose. If they are, tighten them up and see if that solves the problem. If not, then you may need to replace your starter solenoid.

2. Car Won’t Start or Intermittent Starting:

A very common symptom of a bad starter solenoid is that your car won’t start. This is usually the first symptom that you will notice.

If your car won’t start or dies after starting and you know that the battery is charged, then it’s likely that the issue is with the starter solenoid. A bad starter solenoid can prevent the engine from starting for several reasons.

The most common reason is that the magnetic field is not actuating the plunger inside the solenoid. This can be caused by a problem with the coil, connections, or switch inside the starter solenoid.

Another possibility is an issue with the circuit between the battery and starter solenoid. This can be caused by a loose connection, a bad fuse, or other electrical problems.

If the starter solenoid is not receiving enough electrical current, it will not be able to activate the starter motor properly. This can cause your car to turn over slowly or not at all. Additionally, a bad starter solenoid can also cause the engine to stall or die while running.

At times you might face intermittent starting issues. This happens when the starter solenoid is not getting enough power to engage the starter motor consistently.

If you’re having intermittent starting issues, it’s important to check all of the connections in the starter circuit to see if they are loose. Additionally, you should check the battery to ensure it is fully charged.

3. Grinding Noises:

Another symptom of a bad starter solenoid is grinding noises. If you turn the key to the “start” position and you hear grinding noises, your starter solenoid is likely going bad.

The major reason for this noise is that the solenoid is not engaging properly. If the solenoid is not engaging the pinion gear, it can cause the gear to grind against the flywheel or other gears in the starter system.

This can create a loud grinding noise that may be noticeable when starting the engine. Additionally, if the grinding noise is accompanied by a burning smell, it’s likely that the starter solenoid is overheating.

Overheating may occur if the starter solenoid is getting too much electrical current. This can be caused by a problem with the battery, starter circuit, or connections in the starter system.

4. Starter Remains Engaged:

Another symptom of a bad starter solenoid is that the starter remains engaged after starting the engine. This can happen for several reasons.

One possibility is that the plunger inside the starter solenoid is sticking. This can cause the electrical current to remain on even after you turn the key to the “off” position.

Another possibility is that there is an issue with the switch inside the starter solenoid. If the switch is not working properly, it may not be able to turn off the electrical current to the starter motor. Or the solenoid may not be releasing the starter drive gear from the flywheel. This will keep the starter engaged even after the ignition key is turned to the “off” position.

If you notice any of these symptoms, it’s important to have your car checked by a mechanic as soon as possible. These symptoms indicate that your starter solenoid is going bad and needs to be replaced.

What Causes a Failing Starter Solenoid?

There are a few different things that can cause a starter solenoid to fail. A few of these are:

1. Age:

One of the most common reasons for a starter solenoid to fail is age. Over time, the plunger inside the solenoid can become worn down. Like all other mechanical components under constant fatigue, even the starter solenoid has a limited lifespan.

Eventually, the plunger will become too worn to create a strong enough connection between the battery and starter motor. When this happens, it can cause starting issues or prevent the engine from starting altogether.

These issues can cause the starter solenoid to fail and prevent the engine from starting. If your car is older, it’s important to have the starter system checked regularly to ensure everything is in good working order.

2. Bad Wiring:

Another common cause of starter solenoid failure is bad wiring. Bad wiring can cause several problems with a starter solenoid, including a loss of power to the solenoid, an electrical short that can fry the solenoid, or simply a bad connection that prevents the solenoid from working properly.

Any of these issues can prevent the starter solenoid from engaging the starter motor, making it impossible to start the engine. If you suspect that bad wiring may cause your starter solenoid issues, it’s important to have it checked by a mechanic as soon as possible.

3. Moisture:

A major cause of starter solenoid failure is moisture. If the starter solenoid gets wet, it can cause several problems. Moisture can cause corrosion on the electrical contacts inside the solenoid, which can prevent them from making a good connection. It can also leave you with corroded battery terminals.

Moisture can also cause rusting and other problems with the moving parts inside the solenoid. These issues can prevent the starter solenoid and starter relay from working properly and cause starting problems.

If you live in an area with a lot of moisture, it’s important to have your starter system checked regularly to ensure that everything is in good working order.

4. Heat:

If your starter solenoid is failing, it could be due to heat. Heat can cause several problems with the starter solenoid, including melting the insulation on the wires and causing an electrical short.

Heat can also cause expansion and contraction of the moving parts inside the solenoid. This can prevent the plunger from making a good connection with the battery terminal or prevent the solenoid from engaging the starter motor.

Additionally, if you live in an area with harsh weather conditions, the starter solenoid may fail sooner than expected. This is because extreme cold or heat can damage the coil and connections inside the starter solenoid.

5. Overtightened Bolts:

Overtightening the bolts can also distort the shape of the housing, which can damage the internal components. This can cause the starter solenoid to fail and prevent the engine from starting.

If the bolts that hold the starter solenoid in place are overtightened, it can cause several other problems. Overtightening the bolts can damage the threads, making it difficult to remove the starter solenoid later on.

How to Replace a Faulty Starter Solenoid?

Fortunately, replacing a starter solenoid is a relatively easy task that most people can do themselves. However, if you’re not comfortable doing it yourself, you can always take it to a mechanic. Let’s get started.

1. Parking the Car:

The first thing you need to do is park the car in a safe and level place. Once the vehicle is parked, set the emergency brake and put the transmission in Park or Neutral. This will prevent the car from rolling while you’re working on it.

If your car has a manual transmission, you’ll need to block the wheels so that the vehicle doesn’t roll while you’re working on it.

2. Preparations and Safety Precautions:

Once the car is parked and in gear, turn off the engine and disconnect the negative battery cable. This will prevent any electrical shocks while working on the starter solenoid.

If you have an aftermarket stereo system or other electrical accessories, you may need to disconnect them before you begin.

Now would also be a good time to cover your fenders with a sheet or towel to prevent scratches.

Some cars have an airbag system that will deploy if the negative battery cable is disconnected. If you’re unsure how to disable the airbag system, it’s best to take the car to a mechanic.

3. Locating the Solenoid:

The starter solenoid is usually located on the fender, near the battery. It’s a small cylindrical device that’s typically silver or black. In some cases, it may be located on the firewall, near the car’s engine.

If you’re having trouble finding the starter solenoid, consult your car’s owner’s manual. Once you’ve located the starter solenoid, you can begin removing it.

4. Remove Covers if Required:

In newer cars, the starter solenoid may be covered by a plastic or metal cover. If this is the case, you’ll need to remove the cover before you can access the solenoid.

With older cars, you won’t need to remove the entire starter assembly to reach the solenoid. Use a wrench or socket to remove the bolts that hold the cover in place. Once the cover is removed, set it aside, so you don’t lose it. You should now be able to see the starter solenoid.

5. Remove the Starter:

With the cover removed, you should be able to see the starter and starter solenoid. Now the assembly of starter and starter solenoid in some cars is such that you will have to remove the entire starter to access and replace the starter solenoid.

If this is the case with your car, use a wrench or socket to remove the bolts that hold the starter in place. Once the bolts are removed, you can pull the starter out of its housing.

If you don’t need to remove the entire starter, you can skip this step. Now that you have access to the starter solenoid, it’s time to remove it.

6. Removing the Solenoid:

Use a wrench or socket to remove the bolts that hold the starter solenoid in place. In most cases, two bolts will hold the solenoid in place. Once the bolts are removed, you can pull the starter solenoid out of its housing.

7. Compare the Old and New Solenoid:

Now that you have the old starter solenoid out take a moment to inspect it. If the solenoid is damaged or corroded, it will need to be replaced.

If the old solenoid looks in good condition, you can try cleaning it before installing the new one. Use a wire brush or sandpaper to remove any corrosion from the old solenoid.

Once you have the new starter solenoid, hold it up to the old one to ensure it’s the same size and shape. If it’s not, don’t try to force it into place. This could damage the new solenoid or your car’s electrical system.

If the new solenoid is the same size and shape as the old one, you can proceed to the next step.

8. Fit in the New Solenoid:

Position the new starter solenoid, so it lines up with the holes in the housing. Once it’s in place, use a wrench or socket to loosely bolt it into place.

Now connect the positive battery cable to the terminal on the starter solenoid. Make sure the connection is tight, so there’s no risk of it coming loose.

9. Reinstall the Starter Solenoid and the Starter:

In some cases, you’ll need to reinstall the starter solenoid before you can reinstall the starter. If this is the case with your car, ensure the solenoid is properly positioned in its housing.

Once the solenoid is in place, use a wrench or socket to bolt it into place. Be sure to tighten the bolts so that the solenoid is secure.

Now you can reinstall the starter. Once it’s in place, use a wrench or socket to bolt it into place. Be sure to tighten the bolts so that the starter is secure.

10. Connect Wiring and Test the Car:

Now that the starter solenoid is replaced, you can reconnect the wiring. In most cases, there will be two wires connected to the solenoid. One will be the positive battery cable, and the other will be a wire from the ignition switch.

Reconnect these wires to their respective terminals on the starter solenoid. Once the wires are connected, you can test the car to see if the starter solenoid is working properly.

To do this, turn the key on the key. You should hear a click as the solenoid engages. If you don’t hear a click or the car doesn’t start, there may still be an issue with the starter solenoid or the starter. If everything seems to be working properly, you can button up your car and hit the road.