Turned the key in your car’s ignition, only to be greeted by a disappointing click or, even worse, complete silence?
Well, you might have a faulty starter solenoid.
The starter solenoid sends power from the battery to the starter, kick-starting the engine.
Not sure if your starter solenoid is the problem?
Don’t worry!
We’ll walk you through multiple ways to test a starter solenoid so you know exactly what your mechanics are doing. We’ll also cover the signs of a bad starter solenoid and what can cause it to fail.
This Article Contains:
- How to Test a Starter Solenoid with a Multimeter (Step-By-Step)
- How to Test a Starter Solenoid with a Screwdriver
- 5 FAQs on a Starter Solenoid
How to Test a Starter Solenoid with a Multimeter (Step-By-Step)
Testing a starter solenoid with a multimeter involves working with your vehicle’s electrical system, which has potential safety risks. That’s why it’s best to leave the testing and diagnosing to experts.
Here are some tools a mechanic will use for testing:
- A set of wrenches and spanners (in case they need to move components)
- A voltmeter or a digital multimeter
- A small jumper wire
Here’s how they’ll complete the job:
Step 1: Locate the Starter Solenoid
To get started, your mechanic will locate the starter solenoid by following these steps:
- Open your vehicle’s hood: Your car’s starter solenoid is located in your engine compartment. The mechanic will release the hood latch near the driver’s door and pull up the hood.
- Find the starter: Your car’s positive battery cable connects directly to the starter. So, they’ll identify the positive battery terminal and follow the positive battery cable to locate the starter motor.
- Locate the solenoid: The solenoid is the small cylinder attached to the top or side of the starter. The starter motor solenoid has three main terminals: two large terminals for the solenoid’s input and output connections and a smaller terminal for the control circuit.
The input starter terminal carries a wire connecting the starter solenoid to the car battery. Meanwhile, the output starter terminal carries a thick wire powering the starter motor.
Step 2: Conduct a Click Test and Check the Battery
They’ll then conduct a click test to see if the solenoid works properly:
- Observe a clicking sound: While someone turns the ignition switch (starter switch), the mechanic will stand near the engine and listen for a distinct clicking sound as it engages.
- If there’s a clicking sound but the starter motor doesn’t engage: The solenoid may be functioning, but the starter motor could be faulty.
- If there’s no sound: The starter solenoid may be faulty or the battery might be dead.
- Test the battery: They’ll connect the positive red wire of the voltmeter to the battery’s positive terminal and the negative (black) wire to the battery’s negative terminal.
- A fully charged battery should read about 12.6 volts. If it’s below 10 volts or there’s no reading, the battery might be dead or discharged.
- If the battery voltage is sufficient but the solenoid produces a weak clicking sound, they’ll check for control circuit resistance.
Step 3: Test the Solenoid’s Current and Control Circuit
The third thin wire connected to the solenoid, often called the ignition switch connection, helps complete the control circuit when you turn on the ignition key or press the start button.
Here’s how the mechanic will check for current flow:
- Check the control circuit with a jumper wire: They’ll connect a jumper cable between the control circuit terminal (the ignition circuit lead) and the input solenoid terminal.
- A solid clicking sound from the starter motor solenoid indicates proper solenoid function.
- If there’s no click, it’s a faulty starter solenoid.
- Check power with a test light: They’ll connect the red wire of the test light to the input solenoid terminal and ground the black wire to any bare metal surface on your vehicle’s body or the battery’s negative terminal of the battery.
- If the test light illuminates, power is reaching the starter motor solenoid.
- If no light appears, there may be an issue with the battery or wiring.
- Check starter solenoid power transfers: They’ll shift the test light’s red lead wire to the output solenoid terminal and keep the black lead grounded. The mechanic will turn on the ignition key or press the starter button and observe the light.
- If it doesn’t light up, the solenoid isn’t transferring power and needs replacing.
- If the light turns on without a clicking sound or starter engagement, you might need a starter replacement.
- If the test light turns on and the mechanic hears a weak clicking sound, they’ll need to measure the voltage drop on the starter solenoid.
Step 4: Measure the Voltage Drop from the Solenoid
Here’s how they’ll go about it:
- Set the multimeter for voltage drop testing: The mechanic will set the multimeter to measure DC voltage at 15 or 20 volts.
- Measure battery voltage drop: While turning the ignition, they’ll check if the battery voltage reading drops from 12.6 volts by roughly 0.5 volts (normal when starting).
- Test solenoid voltage drop: The mechanic will place the multimeter’s positive lead on the output terminal and the negative lead on the input terminal. While turning the ignition switch, they’ll check if the voltage drop matches the battery (about 0.5 volts).
- If the voltage drops as expected, the issue is likely with the starter motor itself.
- If there’s an unusual drop or no change, the solenoid may have internal resistance issues.
But this isn’t the only way to test your starter solenoid.
How to Test a Starter Solenoid with a Screwdriver
The screwdriver test lets you bypass the solenoid and engage the starter motor directly. This can help determine which component is causing the issue.
Here’s how the mechanic will use a screwdriver to test the starter solenoid:
- Locate the two large terminals on the solenoid, which are usually two metal screws or pins.
- Use an insulated handle screwdriver to connect the two terminals, ensuring its metal shaft touches both terminals to create the connection.
- If the starter engages and turns the engine, the motor works fine, and the issue may be with the solenoid or ignition switch.
- But if the starter motor doesn’t engage, the solenoid might be good. You’ll then have to check your starter motor, battery, or wiring for potential issues.
Got more questions?
We’ve got all the answers you need.
5 FAQs on Starter Solenoid
Here are some commonly asked questions about a starter motor solenoid:
1. How Does a Starter Solenoid Work?
A starter solenoid is a part of the starter circuit. When you turn the key, a small electrical current activates the solenoid, which closes the connection between the battery and the starter motor. This allows a larger current flow to the starter motor, which cranks the engine. Once the engine starts, the solenoid stops the electrical current from reaching the starter motor.
NOTE: A safety switch prevents the engine from starting under unsafe conditions. For example, in automatic transmissions, the safety switch or neutral safety switch only allows the engine to start when the gear is in ‘park’ or ‘neutral.
2. Can You Bench-Test a Starter Solenoid?
Yes, you can bench-test a starter solenoid by connecting it to a battery with a jumper cable. Mechanics usually listen for a solenoid click and use a multimeter to check voltage and continuity.
But if there’s no click, continuity, or voltage at the starter terminal, it indicates a bad solenoid. This way, mechanics can isolate the solenoid and check its electrical performance outside the vehicle. It helps them diagnose whether a no-start issue is due to a faulty solenoid or other electrical problems in the starting system.
3. What Are the Signs of a Faulty Starter Solenoid?
Some symptoms of a bad starter solenoid are:
- The engine doesn’t start
- No clicking noise or single click when starting the engine
- Slow or no cranking
- Smoke or burning smell
NOTE: Some of these signs can be similar to symptoms of a faulty starter relay. That’s why you shouldn’t attempt a DIY and leave the troubleshooting to experts.
4. Why Is Your Starter Solenoid Faulty?
Here are some reasons why your starter solenoid doesn’t work:
- Dead battery, loose battery cable, or corrosion in the terminals
- Faulty wiring
- Worn-out internal components
- Oil leaks
5. How Long Does a New Starter Solenoid Last?
A starter solenoid can last around 60,000 and 90,000 miles, depending on how you drive and maintain your car.
However, bad driving habits, frequent short trips, or a faulty ignition switch can cause a starter solenoid to fail sooner.
Get Easy Starter Solenoid Replacement with AutoNation Mobile Service
A bad starter solenoid can leave you stuck with a car that just won’t start or cause frustrating intermittent starting issues, making your vehicle unreliable.
If you’re looking for expert mechanics to get your car back on the road — call AutoNation Mobile Service.
We’re a mobile auto repair and maintenance service available seven days a week. We also offer a 12-month, 12,000-mile warranty on all repairs.
Contact us to get your starter solenoid or any other part fixed right from your driveway.