How To Do Bench Testing A Starter – A Detailed Guide

Your car’s starter motor may be malfunctioning if you’re having issues starting it. Thus, you can have it tested by your mechanic or at an auto store to know what happened.

Fortunately, bench testing a starter can be an ideal checking method you can do at home. Although it is straightforward to finish by yourself, there are some notes and tips for easier operation.

It can help you save a lot of time and money. Thus, let’s scroll down for more useful information.

Why Do We Need Bench Testing A Starter?

Bench Testing A Starter

As the name implies, you can understand this method is testing a starter motor on the bench.

It’s a fantastic idea to see if there are any issues with this engine. For example, when you meet these situations, you might apply this test:

  • Turn the car key to start, but nothing happens.
  • Turn the car key and hear a clicking sound, but the car cannot start.

Instead of spending time checking it at an auto shop, you can do it at home. This way, you can also save money.

You must take the starter out of the car because this is an off-car check. The other steps will be easy if you know how to remove this part.

Moreover, you should charge the battery beforehand and ensure it is still good.

How To Bench Test A Starter Motor


  • Battery jumper cables.
  • Battery (in good condition).
  • Vise.

Step-by-step Instructions

Step1: Remove your starter

If the electrical circuits are still good, but there is no sound when you try to start your car, the starter may be malfunctioning.

You need to carefully unplug its wires, unbolt, take it out from the engine block, and remove it to conduct additional testing.

Remember to mark all the wires and keep track of the bolts for reassembly if you decide to do this step yourself.

Then, place it in the vise that you have prepared.

Step 2: Attach the starter to jumper cables 

Connect one end of the red jumper cable to the positive terminal of a car battery. Attach the other end to the starter solenoid’s positive post.

The black jumper cable should have one end connected to one of the starter’s ears (the fin-like protrusions from the main cylinder) and the other end connected to the negative battery terminal.

Step 3: Attach a wire to the small terminal of the starter

Take a couple of feet of 16-gauge insulated wire. Trim the end and crimp it onto the starter’s tiny terminal. Continue to strip the opposite end, but don’t handle it just yet.

You might ensure the starter is fixed with the vise.  If it is not in a vise, remember to have something or someone tightly grip this part.

The starter might shift around and discharge some sparks when you do the test.

You might ask someone for help. While conducting the test, have them maintain a firm grip on the starter with a foot. Holding it with your foot can prevent it from jumping around and hurting someone.

Step 4: Connect the wire’s other end to the positive battery post.

The starting pinion should move and spin after you do this step. Yet, if not, the starter needs to be replaced because it is defective.

In addition, have a mechanic perform a more comprehensive inspection if the starter does spin, but you can still not determine the cause of the car’s failure to start.

Final Result

Of course, it is important to understand the final result. So, you can conclude what happened to the starter and have a proper solution.

Bench testing the starting motor will only yield one of three outcomes.

  • The starter motor can work, and the pinion gear will begin to spin quickly and easily. The starter motor is functional if this occurs.
  • The pinion gear of the starter motor will begin to rotate very slowly. The part is damaged in this case.
  • Alternatively, all you’ll hear is a loud click. The outcome informs you that this component is also bad. Fix it as soon as possible, or the starter might burn out.

Another Way To Test A Starter

While the bench test starter requires removing the part, you can do it directly on the car. So, how to test starter motor without removing the element?

The tool you need: A test lamp or digital voltmeter if you know how to read the outcome correctly.

Step 1: Check Solenoid Control Terminal’s Voltage

First, use a voltmeter to measure the voltage at the solenoid’s “S” terminal.

Place the black lead of the voltmeter on the starter motor’s casing and the red lead probe on the solenoid control terminal. Set the multimeter’s indicator to the mode of the 20V scale.

Step 2: Check Voltage At The Feed Terminal

Place the voltmeter’s red lead on the solenoid feed terminal while leaving the identical black lead on the motor case.

On the solenoid feed terminal, you will gauge the continuous full battery voltage. The engine is malfunctioning if the solenoid feed terminal is not receiving 12-volt power.

Step 3: Check The Solenoid Output Terminal’s Voltage

You might ask a person to help turn the ignition key so that you can check the solenoid output terminal voltage.


How Do You Know If The Starter Motor Is Bad?

A faulty starter can be a reason the car won’t start right after turning off. Here are 4 signs to indicate a bad starter motor:

  • Abnormal sound: loud noise, clicking noise when you try to start the engine.
  • The dashboard lights up, but the engine cannot work.
  • The car engine doesn’t crank even if you restart it many times.
  • The car creates smoke.

Can A Starter Pass A Bench Test And Still Be Bad?

Yes, it can pass the bench test but still be bad. It can happen for many reasons. For example, it might be because of the worn ignition key.

Indeed, when the starter is trying to turn the motor over, it requires a lot of electric currents to activate the solenoid and draw the gear in.


How To Bench Test A Starter Motor

This article has provided you with all the necessary information about bench testing a starter. Now, you know how to do it at home and can save some bucks.

Yet, remember to use the vise or hold it carefully to ensure safety. After you find out the reason, it will be easier to know the solution.

If you can handle the issue yourself, take it to the auto shop before it is too late!

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