How to Test Ignition Switch with A Multimeter? (3 Techniques)

Problems with the ignition system can be a regular occurrence. If any electrical component of your motor vehicle stops functioning, you might be prompted to check the ignition system. You must check the ignition system before removing any electrical parts from your motor vehicle. 

You must be aware of the presence of the ignition system if you drive a car. The ignition system is among the most crucial parts of your vehicle. You cannot start your vehicle in the absence of an ignition system. The ignition system and the ignition lock cylinder work together and turn on your motor vehicle.

An ignition switch is used in the control system of a motor vehicle. The key tends to switch on the car’s electrical operation incorporating the power window and the stereo. Along with the name ‘Ignition Switch’, it is also called a start switch or a starter switch. That means this key powers the ignition system and starter solenoid. Particularly, this works in cars with inner combustion motor engines.

The ignition system is an electrical component that can encounter problems just like many electrical components do. When this problem arises, there is a need to test the ignition system to troubleshoot the problem.

However, as a car owner or as a car mechanic, you may often fall into the problem of how to test an ignition switch. The mechanic may find it strenuous to locate the problems with your ignition switch, but it may not be as tough as it may sound. The task is much easier than you may think. Yet, there are several ways to solve it. But, today I’ll talk about the most convenient one. That is, how to test an ignition switch with a multimeter. 

how to wire in a ignition switch

Let’s get started then. I’ll let you know:

  • What is a multimeter
  • Applications of multimeter
  • How to test the ignition switch using a multimeter
  • Signs Of A Faulty Ignition Switch
  • Essential Tools Needed To Test Ignition Switch 
  • How to test the ignition switch?
  • How to check the components of the ignition system

Before we begin, let us give you a quick informational tour of a multimeter. 

How To Test Ignition Switch With A Multimeter?

Here’s how to test an ignition switch with a multimeter:

  1. Disconnect the battery’s negative terminal.
  2. Locate the ignition switch and its wiring harness.
  3. Set the multimeter to the “resistance” or “ohms” setting.
  4. Test the switch’s continuity by placing one probe on the “IGN” terminal and the other on the “ACC,” “ST,” and “START” terminals.
  5. If the multimeter displays a low resistance reading during all tests, the switch is likely functioning properly. If not, it may need to be replaced.

Remember to follow proper safety precautions and seek professional assistance if needed.

What Is a Multimeter?

A multimeter is a testing device that helps you detect the electric voltage. A multimeter also assists you in detecting current, resistance, and any other related values. It is otherwise known as a volt-ohm meter and is useful for performing complex and simple tests.

 You can measure battery voltage and detect faults using the multimeter. It can also diagnose complex faults. A multimeter has multiple purposes, which is why many electricians use it. It helps them troubleshoot the problems that may arise with the electrical equipment. 

There are mainly two types of multimeters that you can find at houses or with a mechanic/electrician. These are

  • Analog multimeters
  • Digital multimeters

Digital multimeters are more advanced as compared to analog multimeters. It is the choice of many electrical engineers. 

Before discussing multimeter usage, let us look at the multimeter applications. It will help you understand everything about the multimeter and how you can use it to check your ignition system. 

Multimeter And Its Applications 

A multimeter makes different readings possible. However, it depends upon the model of the multimeter. A basic multimeter will enable you to measure voltage, amperage, and the resistance of the electrical component. However, an advanced multimeter can help you check the following things.

  • Alternating current voltage 
  • Amperage
  • Resistance
  • Capacity
  • Conductance
  • Decibels
  • Duty cycle
  • Frequency
  • Inductance
  • Temperature

If you attach any accessory to the multimeter, you can get some additional readings related to:

  • Light level
  • Acidity
  • Alkalinity
  • Wind speed 
  • Relative humidity

A faulty ignition system can land you in trouble because you won’t move your vehicle. You might come across various signs which tell you that your ignition system is under some trouble. Before we discuss the application of a Multimeter in testing your ignition system, we shall discuss these signs. 

How to Know If Your Ignition System Is Faulty?

Your vehicle might show you many signs of a faulty ignition system. Your motor vehicle gives you enough signals before completely breaking down. When your motor vehicle does not start, that indicates one of the most common symptoms. Along with it, if you face any of these issues, you may want to check your ignition system using a multimeter or any device. 

Having A Problem with Turning or Removing the Ignition Key

You might want to consider testing your ignition system if you face trouble when you turn or remove the key from the ignition system. It signals that your ignition system is fairly worn-out. Having your key stuck in the ignition system is a good sign of a faulty ignition system. 

The problems with your ignition system might even cause your car to keep running even after you remove the key from the ignition system. It is not a good sign, and you should immediately look into your ignition system’s workings. 

The ignition system is just another electric component in your car and might undergo wear and tear with time. You can contact your car technician and check whether your ignition system needs a substitution.

Your Car Works Fine but Stops in The Middle of Driving

It is very frustrating to have your car break down in the middle of your journey. It is frustrating, especially when it works normally and then dies suddenly. If you are a victim of this situation, you may want to get the ignition switch of your car checked. 

There is a reason why this happens. Most of the time, it happens because of the poor contacts in the ignition switch. It is a sign that your ignition system needs a replacement or service. 

If you don’t get it checked timely, you might have to face a loss in terms of voltage. A temporary loss of voltage can appear, which can cause your car’s engine to misfire. As a consequence, your engine might even die. 

Wearing out of the ignition switch is a common issue. An ignition switch can wear and tear because of regular use. Regular use, over the years, can cause your ignition switch to corrode. If this issue intensifies, your ignition switch can fail.

Vehicle Accessories Encounter Trouble Powering On

Usually, when you turn on your ignition key, the car accessories should turn on quickly. On switching on your ignition key, the interior lights of your car, dashboard, center console, etc., power on immediately. 

However, you can consider getting your ignition system tested if that does not happen. There is possibly a fault with your ignition system that causes these issues. Another possible reason for this is the issues with the wiring and fuse. 

Your Ignition Switch Works, But the Engine Does Not

When you turn the ignition switch on your vehicle, but it does not start, your ignition system has an underlying issue. It can also happen because of a problem with your starting circuit. 

You can check it by looking at the instrument panel warning light showing up when you turn on the key. It may suggest that your car has a dead battery or loose battery cables. To further check this, try turning the headlights on. If they don’t switch on, there is a problem with your car’s battery. 

However, if all this works fine, you should start worrying about your ignition system. There is probably an electrical defect with your ignition switch, starting circuit, or ignition system.

The Ignition Switch of Your Car Overheats

Well, this is another good sign that your ignition switch needs testing and repairs. Have you ever felt a burning sensation when you touch your ignition switch? It can happen when your car’s ignition switch overheats. 

A possible reason for the overheating ignition switch is its connection to many high resistance cables. These high resistance cables can heat up, causing their terminals to arc. 

As a result, the insulating base of these cables can melt, causing a problem with starting your car. That is why sometimes you feel an aggressive jerk when you turn on the ignition switch. 

Testing Your Ignition Switch

If your ignition switch is in trouble, you might face problems in your vehicle. Getting your ignition switch repaired is better than spending money on buying a new vehicle. Before making any decision about repairing your ignition switch, you should consider testing it first. 

If you want to test your ignition switch, make sure you can access it. You can find the ignition switch by taking off the bottom steering column shroud. The process is not the same for all the vehicles. Many clamps and screws hold your ignition switch in place. 

Once you take off the steering column shroud, you can put your car key into the lock. While doing so, check whether your motor vehicle is in the park gear. This process should also engage your parking brake. 

Now, you can connect the ground alligator clip to the multimeter. Once you attach this back wire to the multimeter, you can connect it to the chassis bolt. A chassis bolt is what keeps the driver’s door in place. 

You can also use the red wire to test your ignition switch with a multimeter, but the black wire called the ground alligator clip should be used. 

Now all you have to do is change the setting of the multimeter to 20 Volt DC. You will see a straight line with three dots below it when you do this. You will find that these dots get positioned to the left of capital V.

When you look at the opposite side of the ignition key, you will see a cylindrical housing. This cylindrical housing will have wires connected to it. 

Now turn on your ignition and touch each metal conductor using your testing probe. Check for the readings on the multimeter. If you lack a multimeter, you can use a test lamp instead. 

If the test lamp lights up, you can consider that your ignition switch works fine. However, if your multimeter does not show any readings, you might have to change your ignition switch. 

Changing Your Ignition Switch

The process of changing your ignition switch depends upon the kind of vehicle you have. It is quite simple for some cars. However, while changing the ignition switch in a few cars, you might have to remove the cylinder lock. You may have to remove the entire ignition system in some cars. 

If the situation demands you to replace your ignition switch, you can do it in the following ways.

  • Cut the power of your ignition system by disconnecting the battery from its terminals. 
  • In the next step, make sure to remove the bottom shroud of the ignition column. If you require it, you can also remove the top cover of the system. 
  • Now, you can easily pull out the power cable from the ignition system. 
  • You might need to remove the whole ignition system at times. To do this, you might require a screwdriver, hex wrench, or a socket which will help you remove it without any complexity. 
  • So, if you have to install a new ignition switch, you can do it in this step. You can install the new ignition switch after removing the previous one. 
  • Now all you have left to do is connect the power cables. Also, ensure that you connect the battery terminals. 
  • The last step involves the testing of the ignition switch. You can do this by using your key. 

If your ignition system still fails, there is possibly a problem with your entire ignition system, and you might have to check your ignition system. 

There are many ways that you can use to check the fault with your ignition system. However, using a multimeter can help you check the problem with your ignition system. There are many techniques that you can employ to testto use test your ignition system with a multimeter. 

Here is a brief description of those techniques.

How to test ignition switch using a multimeter

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If your ignition switch comes with some problematic issues, then it can result in some difficulties for you. Then, how to know what are the faults in your switch or how can you recognize that there are some issues with your ignition keys? These are some signs of that. 

Signs Of A Faulty Ignition Switch: 

  • Your vehicle is stopping unexpectedly.
  • Your vehicle is denying you access. 
  • Your car stands straight after being started.
  • There have been problems while activating the accessories.

As said earlier, you can never power on your car engine without an ignition switch. There are some vehicles that installed the ignition switch as a part of an anti-theft operation. 

My recommendation is to get a multimeter for testing whether your ignition switch is functioning or not. A question may come from the other side, why should I use a multimeter? You should use a multimeter as it checks for both AC and DC voltage, resistance, and current. 

Here, I’m showing multiple techniques that you can utilize to examine the working ability of an ignition switch. In doing so, you can use not only a digital multimeter but also an analog one as well.

Essential Tools Needed To Test Ignition Switch: 


A Multimeter

A Replacement Ignition Switch.

An Automotive Wiring Diagram.

A 12 Volt Test Light

Technique 1

  1. Set your fuse panel under the steering wheel. Then, open it. Snatch the starter signal’s fuse. You can do it by taking the fuse pullers positioned on the fuse panel.
  2. Now, cautiously scan your metal strip. Then, assure that it hasn’t got destroyed or flushed. Once your fuse gets destroyed, change it with an operational element of the same intensity as the aforesaid one.
  3. Roll the dial on a digital multimeter to the “volts” indication once your car’s hood is opened. Keep the black lead on the digital multimeter to the covering of your car as well as the positive port of the battery. Connect the red lead of the multimeter. If your battery is good enough to function, the voltage is supposed to be nearly 12.6 Volts.

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If the voltage is slighter than 12 volts, then you have to replace the battery. Perhaps, your battery is not functioning or it’s deceased. Power up the engine by using the ignition key within the ignition switch. As you have come to know that the ignition switch is working well when you can get your engine starting appropriately.

And when the engine is not being started, twist the ignition key to the (III) direction. Provided that it is not getting started even, then check whether there is any clicking noise. If you can hear any sound, then there should be some problem in your car. However, don’t worry, this time the problem is not with your ignition switch. 

On the other hand, if there is a clicking tone while keeping the ignition key at (III), as well as your engine is not working, then be sure that your ignition switch has broken. That is why you will have to renovate your ignition switch.

Technique 2

Automotive Wiring Diagrams

To know what your car’s wiring diagram is, you have to know it. You can simply get it by checking Automotive Wiring Diagrams.

  1. Discard one wire, then lift an old spark plug to the end of the plug boot. After that, search for a metal surface on the engine. As soon as you have put the keys into the switch, power on the vehicle engine. Now, check for a spark on the old spark plug. Assuming that you don’t find any spark on the plug, then it is very sure that the ignition switch needs a change certainly.
  2. You can simply do it by having your multimeter on. Look at the voltage reading is there on the positive end. Do it keeping your key in the switch, and having your ignition switch on. After that, position the red lead on the positive end of the coil. Besides, spot the black lead of the voltmeter on the negative battery terminal, place the black lead of the voltmeter. After that, keep the ignition in the run position once it is turned on. When your ignition switch is operating properly, you should find the voltage of your battery showing in the positive end. On the other hand, when you can’t get any voltage reading, or there is very low reading, it is not a good sign. It indicates that there are some troubles in ignition wiring or the ignition switch.
  3. Place the positive cable of the ignition. Then, swivel the ignition key to the ‘run’ direction. Don’t turn on your engine just after that. Grip the multimeter’s red lead. After that, tug the ignition module wire through it. Make sure that your battery’s voltage is scanning the cable. When you don’t find any voltage reading, probably here is an open circuit in between your ignition switch and the wire.
  4. Operate the negative cable into the red lead of your multimeter. Then, you should deduct the cap on the distributor. But, you should do it without bringing out the spark plug cables. Power on the engine, or fluctuate the center shaft on the distributor by your hand. Check the distributor rotor sharply as your engine starts moving. When your rotor isn’t turning, your distributor isn’t functioning. At this point, the multimeter should be reading zero or the battery’s voltage if the ignition switch and the distributor are working. When the multimeter can’t display the valid voltage, your ignition switch may be changed.

Technique 3multimeter is functioning

  1. Make sure that the multimeter is functioning by swerving the resistance to “XI.” It occurs once you turn on the multimeter as well as select the ohm function. Assuming that, there is a zero resistance, then the VOM is still performing.
  2. Then, swivel your ignition key until it gets on to the off state. Keep the positive lead to the rear side of your ignition switch’s power supply cable. And keep the multimeter’s negative lead to the surface base of the distributor.
  3. Check the battery’s voltage with the multimeter. Make sure that the ignition key is at the state on your ignition switch. When you get the reading is around 90% of the voltage of your battery, then there’s something wrong in the ignition system.

You can use these techniques to check the faults with your ignition system. But what if you want to check the independent components using a multimeter? 

Let us guide you on using the multimeter to check these parts. 

Ignition System: Checking its Components 

Spark Plugs

Testing the spark plugs can be one of the most knee-bending tasks. If your ignition system is at fault, there is probably a problem with the spark plugs. It is the first thing you must check, and you can do so by using two methods. All you will need is a ratchet arm and a special spark plug socket to fulfill this task. 

The first method involves removing the spark plug wires. You can use the socket to unscrew the spark plug wires. After taking out the spark plug wires, you can check whether it is working or not.

 Next, you can put it back into the wire. After doing so, make sure to connect the jumper cable to the ground and spark the plug’s thread. If you see any sparking, you can consider that your spark plug is working. 

You might want to know the second method since it is comparatively easy and safe. In this method, make sure that you change the setting of the multimeter to 20k ohm. Now use one probe to touch the top of the spark plug. You can use another probe to touch the small tip lying below the hook at the bottom of the hook. 

Now, you can close the circuit by touching the rod lying in the center of the spark plug. Now, check for the readings on the multimeter. There should not be any readings on the multimeter if the spark plug works perfectly. However, if the multimeter shows any reading, you might want to consider getting it repaired.

Spark Plug Wires

Spark Plug wires are another component you should consider checking when your ignition system starts troubling you. If you wish to check the spark plug wires, you can set the multimeter to the lowest ohm value. Now, connect the probes inside the wire. 

If the process does not show any resistance, it is time to get your spark plug wires replaced. If you do not do this, your car’s engine might not run in its best capacity. 

Ignition Coil

Take out the two towers of the ignition coil to test your ignition coil. If you do this, you will read the multimeter without much hassle. Find the optimal reading of the ignition coil in the manual that comes with your vehicle. After this, check for the ohm reading on the multimeter. It will help you find whether the ignition coil is working fine or not. 

Crankshaft Position Sensor

You can take someone’s help to test the crankshaft position sensor since you might not be able to do it alone. You may also go through the user’s manual, as it will guide you in testing the crankshaft position sensor

Now, you must ensure that the multimeter is set to 200 Volt. You should also ensure that you put it in the AC setting. After doing this, you can put the probes in the power jack once you disconnect the crankshaft position sensor. 

The other person helping you can crank the engine, and you can check the readings on the multimeter. If the multimeter reading does not match the one given in the user manual, you will have to replace the crankshaft position sensor.

If you need to replace the crankshaft position sensor, you can do it without much difficulty. You only need to take it out and substitute it with a new crankshaft position sensor. 

Ignition Power Supply

It can be a challenging task to locate the ignition power supply. You can try locating it behind the ignition coil. Before proceeding, make sure that you disconnect the cable. 

After disconnecting the cable, you can turn on the ignition key. Further steps involve setting the multimeter to 20 Volts DC. To test the ignition power supply, you can ground the wire and probe the power supply. 

If you do not observe any voltage reading, it is time to get your ignition power supply repaired. However, if the multimeter shows a voltage reading, there is no problem with the ignition power supply of your ignition system. 

There can be a problem with any of the discussed parts in the ignition system. However, if all these parts work fine, you might have to check and replace the entire ignition system. 


How can you tell if ignition switch is bad?

Symptoms of a bad ignition switch include difficulty turning the key, stalling, issues with dashboard lights, and inability to start the vehicle. If you experience these symptoms, consult a mechanic for diagnosis.

How do you jump an ignition switch?

Jumping an ignition switch requires connecting a jumper wire from the battery’s positive terminal to the positive terminal of the ignition coil. This bypasses the switch, allowing the engine to start. This method should be used cautiously and only in emergencies.

How do you tell if it’s your starter or ignition switch?

To determine if the issue is the starter or ignition switch, listen for a clicking noise when starting the car. A clicking noise suggests a faulty starter, while the absence of noise may indicate an ignition switch problem.

How Can I Use the Multimeter to Check My Ignition System?

We have mentioned three techniques to help you check the ignition system using a multimeter. You can use these techniques and check whether your ignition system is fine or not. 

Do I Need to Replace the Ignition System If It Breaks Down?

Yes, you will have to replace the ignition system if it breaks down.


Hopefully, you have already solved this problem. If you have anything to know, then let us know in the comment section below. And if you have any more questions on how to test an ignition switch with a multimeter, then feel free to ask us below.

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