A starter motor solenoid sounds like something from another planet, but it is actually a critical part of cars with an internal combustion engine. We’ll explain what it is, why it’s important, and how it works.
What Is a Starter Motor Solenoid?
The starter motor solenoid plays a crucial role in starting the car’s engine, ensuring the starter motor gets enough power to start the engine. It acts like an intermediary between the ignition switch and the starter motor. It closes the circuit within split seconds, helping to manage the high current and preventing damage to the ignition switch.
How Does a Starter Motor Solenoid Work?
When you turn the ignition key in your car, an electrical current flows from the battery to the solenoid, creating a magnetic field. It is a low-voltage signal that is sent to the solenoid to tell it to get to work. There is a plunger inside the solenoid, which is pulled when the magnetic field is created, closing the gap. Once this is closed, the high-current power from the car’s battery moves to the starter motor to crank the engine.
Common Signs of a Failing Starter Solenoid
Given that a starter motor solenoid plays a critical role in starting a car’s engine, it will become apparent to you when it is failing.
Clicking Sound When Turning the Key
This clicking noise occurs when the solenoid is trying to engage but is failing to do so properly. It’s one of the most common signs of the starter solenoid failing and is usually accompanied by the engine not turning over.
Intermittent Starting Issues
Inconsistency when starting your engine could be a sign that your starter solenoid is failing. While it may work fine one minute, the next time you go to start the engine, you may need to try multiple times.
No Response When Turning the Ignition
If nothing happens when you turn the key in the ignition, the starter solenoid may have failed completely. In this situation, then the car won’t turn over at all, and it is likely that your starter solenoid needs to be repaired or replaced.
Smoke or Burning Smell
In serious cases, a faulty starter solenoid may cause excessive heat buildup, leading to a burning smell or smoke coming from the engine bay. In such scenarios, it’s important to seek help immediately, as it can be a sign of dangerous issues like an electrical short.
Troubleshooting a Faulty Starter Solenoid
Checking the Battery First
If your car’s battery is weak or dead, it may actually display the same symptoms of a failing starter solenoid. To be sure of the problem, it’s advised to test your battery’s voltage with a multimeter. Your battery should read around 12.6 volts when it is fully charged. If the battery voltage is low, this may be the problem, so you should charge or replace it.
Inspecting the Solenoid Wiring
It’s important to inspect the wiring connections to the starter solenoid because loose or corroded wiring could prevent it from functioning properly. Make sure that this is clean and tight and check for signs of corrosion around the terminal connections. Replacing damaged wires and cleaning the terminals with a wire brush could resolve the issue.
Testing the Solenoid with a Multimeter
A multimeter will be able to test your starter solenoid’s operation. Have someone help you do this. Set the multimeter to the DC voltage setting and check the solenoid’s input and output terminals while someone turns on your car’s ignition. If there is no voltage at the output terminal, then the starter solenoid is probably defective.
Temporary Fixes for Emergency Situations
Sometimes tapping the solenoid gently with a hammer can temporarily free up any components of the starter solenoid that might be stuck. It’s important to note that this is a short-term solution and should be followed up with a repair or replacement as soon as you can get to a mechanic.
Maintenance Tips to Extend the Life of Your Starter Solenoid
If you take care of your starter solenoid, it is likely to last longer and perform more reliably. Simple regular maintenance could help extend its lifespan.
Keeping the Electrical System in Good Condition
The starter solenoid is heavily connected to your car’s electrical system and relies on it to function properly. It’s recommended to regularly check connectors and wires to ensure there is no damage or corrosion. You should also keep the battery terminals clean and ensure electrical connections are tight.
Regularly Checking Battery Health
One of the primary reasons for starter solenoid issues is a weak or failing battery. Check your battery’s voltage from time to time to check that it is charged and in good condition. You can do this with a multimeter to check its condition, ensuring that it is around 12.6 volts when fully charged. If there are any signs of battery deterioration, it’s a good idea to replace this as it is likely causing strain on your car’s starter system.
Avoiding Frequent Short Trips
When you take short trips, your car’s engine and electric system don’t have enough time to fully recharge its battery. Frequent short trips can also mean that the engine doesn’t reach its optimum temperature. This leads to unnecessary strain on the starter solenoid and means that the electrical system doesn’t have enough time to fully recharge the battery, shortening the starter solenoid’s lifespan. It’s advised to take longer drives from time to time to allow the car’s battery to recharge fully.
When to Replace Your Starter Motor Solenoid
Signs that indicate replacement is necessary
If you hear a clicking sound when turning the key in the ignition, have intermittent starting issues, no response when turning the ignition, or notice a smoke or burning smell, it’s likely that your starter motor solenoid may need replacing.
Estimated cost and what to expect
The cost of a new solenoid is generally between $30 and $100, though this can increase if you’re buying a complete starter motor with the solenoid included.
The labor cost of replacing the solenoid is usually between $75 and $100 and can take between 1 and 2 hours. So, in total, the cost of replacing a faulty solenoid is likely to be between $150 and $300. However, if you replace the entire starter motor and the solenoid as a combined unit, this will be more expensive and can be up to $500.