How to test the ignition switch with a multimeter (step by step) (2023)

Are you trying to start your vehicle and the engine just won't turn?

If so, the problem may not be with the engine, but with a culprit that isn't normally investigated like other vehicle components.

This is your ignition lock.

The ignition switch is an electrical component, usually located next to the steering wheel, used to start a car.

If it is defective, do not wait for your motor or electrical accessory to start.

Not many people know how to diagnose this electrical component, so we are here to help.

we will show you6 proven methodsto check the ignition switch with a multimeter.

Let's go right in.

How to test the ignition switch with a multimeter (step by step) (1)

Symptoms of a bad ignition switch

There are many signs on cars that indicate a bad ignition switch.

In addition to your vehicle not starting, other symptoms of a bad ignition switch include:

  • Difficulty removing or turning the ignition key, indicating a worn ignition switch. It may also indicate that the key in the switch is not connected properly.
  • The engine will continue to run after the switch is turned off and the key is removed.
  • The car stalls while driving which could be the engine losing power through the switch.
  • Car accessories will not work even if the ignition key is turned to the run position
  • The power switch is hot when you touch it. This indicates a fault in the electrical system.
How to test the ignition switch with a multimeter (step by step) (2)

If you are experiencing one or more of these symptoms, your ignition switch could be to blame and may need to be replaced.

When testing electrical components, a multimeter is avaluable tool.

How to test the power switch with a multimeter

Turn the key to the run position, set the multimeter for a voltage of 20 DC, ground the black lead to a nearby metal surface, and connect the red lead to a connector on the opposite side of the ignition barrel. If the multimeter shows a reading far from battery voltage, the switch is faulty.

There is more to this process, as well as other techniques you can use to diagnose your ignition switch.

Step 1: Remove the panel under the steering wheel

To test your ignition switch with the first method, you'll need to remove the casing that covers the other parts of the switch.

(Video) How to test an ignition switch

This is the panel under the steering wheel, and you will remove it to reveal the metal connectors on the other end of the switch.

Step 2 - Set the multimeter to the 20 DC voltage range

Your car uses direct current (DC voltage) and this test takes your battery voltage into account.

With voltage typically around 12 volts, set the multimeter scale to the 20 DC range, as this will ensure an accurate reading.

DC voltage is usually represented by "V with a dash and three dots next to it."

Step 3 – Place the Multimeter Probes in the Car and the Ignition Switch

Ground the black (negative) probe of the multimeter to any metal part of your car. This can be a nearby screw or even the body of your car.

Place the multimeter's red (positive) probe on one of the metal terminals on the other side of the ignition switch.

This is the opposite end of the switch barrel where the wires connect and these are important when checking to see if the ignition switch is passing power or not.

Step 4 – Flip the switch on and evaluate the results

Now, without trying to start the engine, turn the key to the run position and see what the multimeter indicates.

A reading close to battery voltage means the ignition switch is working properly.

For example, if you are using a 12 volt battery, a reading of 11 volts is still significant and means that the ignition switch is working properly.

If the multimeter gives you a 0 or a reading outside of that range, the ignition switch is faulty and needs to be replaced.

Method 2 – Test the Fuse and Battery

Step 1 - Open the Fuse Box Under the Steering Wheel

With the second method, the panel under the steering wheel also opens.

This is done to expose the starter fuse instead of the metal terminals on the other end of the switch.

How to test the ignition switch with a multimeter (step by step) (3)

Step 2 - Remove the Start Signal Fuse

Now use your fuse pullers to pull the starter signal fuse out of the socket it is inserted into.

Step 3: Check the fuse

Check the metal strip on the fuse to see if it is in good condition.

If you suspect damage, simply replace this component with a new one with the same amperage. Make sure this new backup actually works.

(Video) Discover How To Test Your Entire Ignition System With One Simple Tool

Step 4: Check the battery

They also check that your battery is not damaged, and that's where a multimeter comes in.

Ground the multimeter's black probe to a nearby metal surface (perhaps the body of your car), and then place the red probe on the positive battery terminal.

If the multimeter does not read near 12 volts, it should be replaced.

Once you've replaced it, or if it's still in good condition, move on to the next step.

Step 5 – Flip the switch on and evaluate the results

The final step here is to turn the ignition switch to the start position and see if the engine starts.

If the engine starts after replacing these components, then those were the culprits.

If the engine won't start but you hear a click when you turn the key, the ignition switch is working properly and the problem lies elsewhere.

If the engine won't start and you don't hear a click, your ignition switch is faulty and needs to be replaced.

Method 3: Spark Plug Test

Locate the spark plug in your engine and remove one of the wires attached to it.

Insert an old spark plug into the end of the spark plug, and then place the metal part of the spark plug on any metal surface near you.

Start your engine and look for a spark at the old spark plug (an assistant can do this for you).

If you don't see a spark, the ignition switch may be faulty and you need to replace it.

How to test the ignition switch with a multimeter (step by step) (4)

Method 4: Ignition Coil Test

You can also test your car's ignition coil.

If your multimeter is set for DC voltage, place the red probe on the positive terminal of the coil and the black probe on the negative terminal of your battery.

Without starting the engine, turn the key to the on position and see what the multimeter reads.

A good ignition system would expect the multimeter to output around 12V.

(Video) How to Test a Riding Lawnmower Key Switch

If the multimeter does not give you a reading close to this value, or if you get no reading at all, the ignition switch, wiring, or coil may be faulty and need to be replaced.

How to test the ignition switch with a multimeter (step by step) (5)

Method 5: Test with ignition module

There are two tests you can run on yoursZündmodul.

In the first step, place the black lead of your multimeter on the negative pole of your battery and the red lead on the positive pole of the ignition module.

Without starting the engine, turn the key to the on position and see what the multimeter tells you.

If you don't get a reading, there may be an open circuit between the ignition module wire and your switch.

The second test also involves using your dealer.

Remove the distributor cap, attach the black multimeter lead to the negative battery post, and the red multimeter lead to the ignition module negative lead.

Rotate the center shaft of the distributor and see what the multimeter reads. If the ignition switch and distributor are working properly, the multimeter is expected to read zero (0).

If you get a multimeter reading, there could be a problem with the ignition switch wiring and you're looking for ways to replace it.

Method 6 – Check Continuity at the Ignition Switch

A final diagnosis tests whether the ignition switch has continuity in its circuit. This is where you completely disconnect the power switch from any other accessories.

The ignition switch normally has five terminals.

  • Time (G)
  • Magnet (M)
  • Starter(S)
  • light (L) and
  • Batteries (B)

Set your multimeter to continuity or ohms mode and make a note of these positions for routing your multimeter's leads.

If you put the black probe on the metal body of the switch and the red probe on the "G" terminal, there should be continuity only when the switch is off.

Also, if you connect the black probe to the "G" terminal and the red probe to the "M" terminal, expect continuity only when the switch is off.

For the "B" and "L" terminals, you now expect continuity only when the switch is flipped to the "on" position.

That is, while the switch is off, the multimeter is expected to remain silent or read "O.L".

(Video) How to diagnose a No Start Condition - Ignition Switch

Expect continuity between the "B" and "S" terminals only when the switch is in the "Start" position. That means it is expected to remain silent in the on and off position.

If this is confusing, here is a video showing how to make aContinuity test on an ignition switch.


There are several methods to test whether your ignition switch is in good condition or not.

However, the first and last methods are the best to directly determine if the power switch is working or not.

Other tests help diagnose other components within the ignition system that could be additional culprits.

frequent questions

How do you bypass a power switch?

Connect the positive pole of the ignition coil and the starter cable to the positive pole of the battery. Disconnect the shift cable from the solenoid anddirectly connect the red Cableon the solenoid to that point.

How can I start my car without the ignition switch?

Remove the panel under the steering wheel and locate the brown jumper cables and the red battery cables. Twist the red wires together and thenTouch the brown wires togetherto start the engine.

Can a bad ignition switch drain the battery?

A bad ignition switch only drains your car battery if you can't turn it off. It can also drain slowly if you repeatedly try to start the car without success.

How to test the ignition switch with a multimeter (step by step) (6)

Alex Klein is an electrical engineer with over 15 years of experience. He is the host of the Electro University YouTube channel, which has thousands of subscribers.

(Video) no start / crank : troubleshoot the ignition switch


How can you tell if ignition switch is bad? ›

Symptoms of a Bad Ignition Switch
  1. Engine Won't Start. ...
  2. Vehicle Starts and Suddenly Stalls. ...
  3. Intermittent Loss of Lighting and Other Accessories. ...
  4. Silent Starter Motor. ...
  5. Difficulty Turning the Key. ...
  6. Lock/Off. ...
  7. Accessory. ...
  8. Run.
Sep 14, 2022

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

Starter motors should make noise when you turn your ignition key fully to activate your car. If you turn the key and do not hear anything, there's a chance that there's something wrong with the vehicle's ignition switch.

How do you check an ignition switch fuse? ›

  1. Step 1: Turn Your Car Off. ...
  2. Step 2: Locate Your Fuse Box. ...
  3. Step 3: Connect to Ground Point. ...
  4. Step 4: Test Fuses with Your Circuit Tester to Find Constant Fuses. ...
  5. Step 5: Test Fuses with Your Circuit Tester to Find Switched Fuses. ...
  6. Step 6: Connect Your Accessory to the Identified Constant and Switched Fuses.

How do you jump an ignition switch? ›

Connect the positive terminal of the battery to the positive side of the ignition coil. Also, identify the starter solenoid and connect it to the positive terminal of the battery. Next, unplug the ignition switch wire from the solenoid and then short the solenoid's terminal to reach where the ignition switch connects.

Is there a fuse for the ignition? ›

The ignition relay is one of the most important electronic relays found on modern vehicles. It is usually located in the fuse and relay panel beneath the bonnet, and is responsible for providing power to the vehicle's ignition system, and some of the fuel system's components.

What causes no crank no start? ›

If your vehicle won't start, it's usually caused by a dying or dead battery, loose or corroded connection cables, a bad alternator or an issue with the starter. It can be hard to determine if you're dealing with a battery or an alternator problem.

How do you test an ignition wire with a multimeter? ›

To do this, set the multimeter to the appropriate scale and measure the wire by placing the probes on each end of the wire lead, making sure they touch the metal contacts. If the reading is within the manufacturers' guidelines, the wire can be returned to the car before you start to test the next wire.

Does ignition need to be on to check fuses? ›

Yes. Always ensure to turn off your vehicle's ignition and disconnect the battery before you open or start working on a fuse box.

Where is the fuse for the ignition relay? ›

In most cars, it will be under the hood, in a large box with a black lid. This is where car fuses and relays are installed. It is also called a fuse box. This box is usually installed on the driver's side of the vehicle.

What are the 5 positions of the ignition switch? ›

The ignition switch has four positions: LOCK (0), ACCESSORY (I), ON (II), and START (III). Use this position only to start the engine. The switch returns to the ON (II) position when you let go of the ignition switch.

Can I bypass ignition switch? ›

Bypassing a broken ignition switch is quite a technical procedure that will require a little more than just a manual and a keen sense of learning. The best case scenario is that you take your car to a professional to handle it or simply just replace the switch. Keep in mind Oznium does not sell ignition switches.

How do you jump start a car with an electric ignition? ›

Simply attach the jump box to your battery, then get into the car with your keyless FOB in your possession, press the start button and it should start right up.

What is the first step in diagnosing an ignition system problem? ›

Test Spark Plug Wires

The first thing to inspect is your plug wires. Any signs of damage or decay are clear indicators that they're your issue. To verify, you'll want to check the resistance of the wires.

What tool is used to test the condition of the ignition system? ›

Although "diagnosable engine management systems" are installed in today's vehicles, a multimeter or oscilloscope must be used when checking ignition systems.

How do you check if a starter is bad with a multimeter? ›

Connect the positive multimeter lead to the high voltage input terminal on the starter solenoid and ground the negative lead on a metal surface using alligator clips. If your starter is good, the multimeter displays 12 volts and this value reduces when you try to start the vehicle.

What is the 5 five common problems for solenoid? ›

Rusting, power failure, irregular pressure, missing equipment, an incorrect amount of voltage or current, dirt stuck in the system and corrosion are some of the possible reasons why a solenoid valve may not properly close or open.

How do I know if my starter relay is blown? ›

If your starter relay has gone bad, the electrical signal will never make it from the battery to the starter motor. As a result, your engine won't turn over - no matter how many times you turn the key. A faulty relay often produces an audible clicking sound when you turn your car.

What blows an ignition fuse? ›

It is very likely there is a short somewhere in the system. If not in the wiring, there could be an issue with the fuse box. This is unlikely if you are not having issues with other circuits. The starter can also cause this to blow.

What sensors cause crank no start? ›

One common culprit for this problem is the crankshaft position sensor, which measures the position and speed of the crankshaft. The computer uses the information from this sensor to know when to fire the spark plugs. If the sensor isn't working, the spark plugs won't fire, keeping the engine from starting.

When I turn my key in the ignition nothing happens? ›

Seriously, if nothing happens when you turn the key there are quite a few things that could be wrong with your car. There is a good chance it's your battery. Look at your cars interior lights to see if you're drawing any power. If nothing is on then it's very likely your battery.

What would cause a car not to crank if battery is not dead? ›

Bad Alternator

If your car won't start, but your battery is fine, chances are you have a bad alternator. This is another charging system issue, like a dead battery, that won't let you start your car.

Is fixing an ignition switch easy? ›

You can replace the ignition switch yourself, but it's not an easy task: you will have to remove the steering wheel and work close to the airbag - which can be dangerous. Don't hesitate to call a professional mechanic if you're not feeling confident.

Do you need a new key when replacing ignition switch? ›

If you have an older model that uses a standard key, you may be able to get away with using the existing key when replacing the ignition switch. But if your vehicle has a specialised security system or a more complex electronic design, chances are you will need to get a new key for the replacement.


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