A large reason for learning how to test a starter with a Multimeter is to prevent and detect future problems such as corrosion or loose or disconnected wires.
When you want to check the starter motor with a Multimeter, you need 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 the reading is zero, it’s good; if OL, then it’s dead.
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 moving around.
Resistance Test of Starter Motor with a Multimeter
This is a Multimeter test where we use resistance to check the condition of the starter motor, and it is done by:
- Turning 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 Multimeter reading 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 Multimeter leads on both solenoid’s heft depots.
- 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
A starter solenoid is activated when a driver turns on the ignition switch. It 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 starter solenoid because starter solenoids are mostly uniform with starter motors. The process for performing this type of car starter test is as follows:
- The first step is to put your starter and solenoid assembly on top of a bench, the garage floor, or any flat surface for those without a benchtop.
- The next step is to 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. It would be best if you made 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 checking the starter to find out whether it is good or bad, which 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 a solenoid, and they are:
- Put your starter in the vice.
- The next step is to attach the negative battery cable o the battery’s negative terminal and 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, it is still good, but if the starter motor does not rotate, it needs replacement.
Points to Consider Before Performing Voltage Drop test
A few things need to be remembered when 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 a 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 them 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 voltmeter reading.
- If the reading of the voltmeter is 0.5 or lower, then the engine ground strap is in good shape, and the ground side works perfectly.
- If the reading is higher than 0.5, then the resistance is high.
- Finally, check for the starter mounting bolts, and ensure they are tight and have a good ground connection with the engine block. You should also ensure 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 to the positive battery post and the negative voltmeter 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.
- The next thing is to locate the place where the resistance is high. 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
- The first thing you need to do is record the (base) voltage reading of the battery, which will be useful when comparing the voltage of the starter motor terminals.
- Next, 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.
- You must now attach the voltmeter’s red lead 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 compare the starter motor’s voltage reading and your battery posts’ base voltage reading.
- 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.
After testing the starter motor and knowing it is good, the starter should be able to hold a charge and produce power. 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)
Take a look at some of our related articles below.
- What wires go to the starter solenoid
- How are voltmeters connected in a circuit
- How to wire fuel pump to ignition switch
(1) electric current – https://www.britannica.com/science/electric-current
(2) electrical problem – https://lsin.panasonic.com/blog/common-electrical-problems-and-solutions/
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