How to Test a Starter with a Multimeter (5-Step Guide)

A large reason for learning how to test a starter with a Multimeter is to prevent problems such as corrosion, or loose disconnected wires.

When you want to check the starter motor with a Multimeter you need some specific tools including a Digital Multimeter, vice, an Alligator clip, two jumper cables, and a fully charged battery.

In general, to test a starter with a multimeter turn on the Multimeter and put the red probe in the V(Ω) socket and the black in the COM socket, set to lowest resistance in ohm mode, then put the black lead of the Multimeter on the starter motor case and the red lead on the starter motor output terminal on the backend of the solenoid lid. If reading is zero, it’s good, if OL then it’s dead.

Safety First

While testing the starter motor, it’s important to disconnect the starter circuit’s wiring, remove the starter motor from the car and unbolt it and place it on a non – conducting surface. Make sure there are no pieces of jewelry or any form of conducting materials, to prevent a short circuit. You may also need to hold the starter in a vice and place your foot on it during testing to prevent it from jumping around.

Resistance Test of Starter Motor with a Multimeter

testing with multimeter

This is a Multimeter test where we use resistance to check the condition of the starter motor and it is done by:

  • Turn on the Multimeter and put the red probe in the omega socket and the black in the common socket of the Multimeter after which you will set the dial range to the lowest resistance on ohm mode.
  • The next step is to put the black lead of the Multimeter on the starter motor case and the red lead on the starter motor output terminal which is found on the backend of the solenoid lid.
  • If the reading of the Multimeter is zero – adjacent then the starter motor is good but if it shows a reading of “OL” then the starter motor is dead.

How to Test a Starter Solenoid with a Multimeter

  • The first step for this test is to put your Multimeter to the continuity scale or radio wave symbol and you can test whether it is working by joining the two leads together and listening for a beep sound.
  • The next step is to put the tip of the two leads of the Multimeter on both heft depots of the solenoid.
  • The final step is to listen for a beep after attaching the two leads. If it produces a beep sound then that means it is bad but if it does not produce a beep sound then that means the solenoid is good.

Bench Test a Starter Motor with Solenoid

testing the starter of a car

A starter solenoid is what gets actuated when a driver turns on the ignition switch. It is what allows electric current to pass through the windings of the starter motor which starts the engine. (1)

To check whether it is functioning properly you need to check the motor assembly and the entire starter solenoid because starter solenoids are mostly in uniform with starter motors. The process for performing this type of car starter test is as follows:

  • The first thing is to put your starter and solenoid assembly on top of a bench or the garage floor or any flat surface for those without a bench-top.
  • The next step is to then connect the jumper cable to the battery by clipping the red lead to the positive battery terminal and the black lead to the positive terminal. You should make sure the free ends of the jumper cable don’t touch each other.
  • The next step is to touch the free jumper cable leads to the starter solenoid by holding the red lead to the starter solenoid and the black lead to the solenoid housing for a few seconds and then disconnect the jumper cables from the battery.
  • The final step is to check the starter to find out whether it is good or bad and that can be done by checking for a click sound while performing the previous step.

Bench Test a Starter Motor without Solenoid

There are three steps involved when you want to bench test a starter motor without solenoid and they are:

  • You need to put your starter in the vice
  • The next step is to attach the negative battery cable o the negative terminal of the battery and also attach the other end to the starter case.
  • The third step is to attach the positive battery cable to the positive battery terminal and then touch the other end of the cable to the starter’s power input connector. The pinion gear will start rotating immediately when you touch the battery wire to the input connective.
  • The final step is to check whether it is good or bad. If the starter motor rotates when you touch the positive wire to the input connective then it is still good but if the starter motor does not rotate then it needs replacement.

Points to Consider Prior to Performing Voltage Drop test

yellow multimeter 1

There are a few things that need to be remembered when you’re performing voltage drop multimeter tests and one is making sure the battery is fully charged because the starter motor draws a huge amount of electric current. A fully charged battery is around 12.6 volts or higher. The next thing to remember is to disable the ignition system to prevent the engine from starting.  Some important tips to remember are:

  • The voltage drop test with Multimeter is only possible with a live circuit.
  • The car battery might contain a surface charge so you should turn on the headlights for a minute and then turn it off to remove the surface charge.

Checking the Voltage Drip of the ground level of the Starter Motor

  • You first need to connect the positive voltmeter-lead to the negative battery post and the negative voltmeter-lead to the starter motor case.
  • Crank the engine for a few seconds and record the reading of the voltmeter.
  • If the reading of the voltmeter is 0.5 or lower, then the engine ground strap is in good shape and the ground side is working perfectly.
  • If the reading is higher than 0.5 then the resistance is high.
  • Finally, check for the starter mounting bolts and make sure they are tight and they have a very good ground connection with the engine block. You should also make sure that dirt or grease does not exist between the engine block and starter motor mounting bolts.

Checking the Voltage Drip of the Positive end of the Starter Motor

  • The first thing is to connect the positive voltmeter lead to the battery positive post and the negative voltmeter lead to the negative battery post.
  • Turn on the ignition switch for a few seconds to crank up the engine and record the reading on the voltmeter.
  • If the reading after you crank up the engine is 0.5 volts or less then the power side of the starter motor is functioning properly, however, if it is higher than 0.5 then that means the resistance is high which is bad.
  • Next thing is to locate the place where the resistance is high and this is done by moving the meter leads closer to each other along the power side of the starter motor circuit gently until you finally reach the actual location where the voltage drops to normal.
  • Always remember that where it drops the resistance after the actual location of resistance has an actual voltage drop.

The Procedure of a Voltage Drop Test with Multimeter

motor engine and multimeter

  • The first thing you need to do is to record the (base) voltage reading of the battery which will be useful when trying to compare the voltage of the starter motor terminals.
  • Next thing is to connect the positive lead of the voltmeter to the battery positive post and the negative lead of the voltmeter to the battery negative post.
  • The next step is to crank up the engine for 11-20 seconds and take note of the voltage reading on your voltmeter. This reading will be your base voltage reading.
  • What you need to do now is to attach the red lead of the voltmeter with the starter motor feeding terminal stud and the black lead to the starter motor casing.
  • Crank up the engine again for another 11-20 seconds and take note of the voltage displayed on the voltmeter screen.
  • You should then compare the voltage reading of the starter motor and the base voltage reading of your battery posts.
  • Check both the readings and if you notice they are the same or the difference is not more than 0.5 volts then that means the connection is good and there is no excessive voltage drop.
  • If however, the voltage drop is not the same and higher than 0.5 volts then that means there is some resistance in the starter motor circuit and you need to find out the exact location of the resistance.
  • To do that you need to perform a voltage drop test at the positive and ground side of the starter motor. I have shown you how to do that above.

Wrapping Up

After testing the starter motor and knowing it is good, the starter should be able to hold a charge and produce power, and if not, then perhaps your problem is an electrical problem or the fault of a circuit or something entirely different. In this case, it is best to contact a professional or someone with expertise. (2)

Below are some other multimeter learning and product guides. You may check and bookmark them for later reading.






References
(1) electric current – https://www.britannica.com/science/electric-current
(2) electrical problem – https://lsin.panasonic.com/blog/common-electrical-problems-and-solutions/

About Sam Orlovsky

b1d87d2ee85af3e51479df87928bdc88?s=90&d=mm&r=gI realized early on carpentry was a huge passion for me and I’ve stayed in the industry for over 20 years now. This gives me a unique ability to really be able to tell you what the best tools and recommendations are. I’m not only a carpenter but I also like machinery and anything to do with electrics. One of my career paths starting off was as an apprentice electrician so I also have a lot of experience with electrical products and anything related.