How To Start A Car With A Bad Ignition Switch? A Step-by-Step Troubleshooting Guide

A bad ignition switch can be an overlooked problem if you can't start your car. Fortunately, you can get around issues with the ignition system.

You can hotwire specific older car models to bypass the ignition switch. Others can be started using a jumper link method. A bad steering wheel lock can be drilled out and turned with a screwdriver.

Here's a guide to getting around a bad ignition switch and how to diagnose an ignition system problem.

How Do You Bypass A Bad Ignition Switch?

If you have figured out that your problem is a broken ignition switch, there are a few methods that you can use to get your car started.

Depending on your vehicle, one of these methods should work to bypass the ignition switch.

Hotwiring

As you may have seen in the movies or on tv, hotwiring starts your car by bypassing the ignition switch.

Unfortunately, this method only works on older vehicles. This is because most cars made after the year 2000 have a different type of ignition system that prevents hotwiring.

If you have an older vehicle, you're still in luck.

The first step to hotwiring your vehicle is to locate and remove the plastic cover over your steering wheel column. This cover often called a clamshell, will have a few small screws that hold it in place.

After removing the steering wheel cover, you must locate the ignition switch wiring harness connector.

This will contain a small bundle of multi-colored wires, each controlling a different function for your ignition and electrical components.

You must identify the wires that control your battery, starter, and ignition.

The red wires are for the battery, the yellow and brown wires are for ignition, and the starter wire is usually green.

Strip around an inch of insulation from the red wires and twist them together. Then strip the same insulation from the ignition wiring and twist it onto the battery wires.

At this point, you should see your dashboard lights start working. This is a sign that your wires are connected correctly.

Then, strip a half inch or so of insulation from the starter wire and touch it to the twisted bundle of the battery and ignition wires.

This should cause your starter motor to work as if you were to turn the key.

Jumper Links

Another method to bypass the ignition switch is using a jumper cable to send the battery voltage directly to the starter and ignition coil.

This method is preferred for modern cars that can't be hotwired.

The first step in this process is to locate the ignition coil for your vehicle and connect the positive lead of the coil to the positive battery terminal using a jumper cable or length of jumper wire.

This will energize your ignition system so your spark plugs will fire when the starter motor is activated.

Once the ignition coil is connected to the battery, locate the starter solenoid. This solenoid is almost always attached to the body of the starter itself.

Connect the lead terminal of the starter solenoid to the positive terminal with a jumper cable.

Once the starter solenoid is connected to the battery, you have to use a screwdriver to bridge the terminals of the solenoid.

Touch the blade of the screwdriver to both of the terminals at the same time, and the starter motor should activate.

Stay clear of the engine once this happens since it should start your car.

The Drill and Screwdriver

A last-ditch method to deal with a broken ignition cylinder and start your car is to drill out the cylinder and turn the ignition with a screwdriver.

This will permanently damage your ignition cylinder, so you should only use this method if you know that the cylinder and ignition switch is the problem.

Using a drill with a small bit around the size of your car key, position the drill bit where you typically insert your car key.

Slowly drill into the ignition cylinder up to the length of your car key. Don't drill any further than this, or you could damage other components inside your steering column.

Once this hole is drilled out, insert a flathead screwdriver into the hole and twist in the direction you would turn the key.

This should have the same effect as turning the car key and should activate the car's ignition switch.

What Are The Signs Of A Bad Ignition Switch?

Since a faulty ignition switch can show some of the same symptoms as a failing starter motor or bad battery, it can be tough to troubleshoot the ignition switch.

You can watch out for a few signs that may let you know that you have a bad ignition switch.

A loose ignition lock cylinder is one sign. If your key doesn't fit in your cylinder, you may have a problem with the ignition switch.

This also applies if you have difficulty when you try to turn the key or if you notice that something feels broken inside the key cylinder.

Another issue to watch out for is problems with your vehicle's electrical systems.

Since the ignition switch connects to your car's electrical system, it can cause problems with specific components if it goes bad.

A bad ignition switch could be to blame if you have problems with your radio or power windows, headlights, interior lights, or wipers.

How To Test Ignition Switch?

There are a few different methods to test the function of the ignition switch.

Test Voltage With Multimeter

One method is to test voltage from the switch's power feed wire using a digital multimeter.

This will show whether or not there is power at the switch itself.

After removing the steering wheel cover, set the reading for your multimeter to 20 DC volts.

Ground the black negative probe to any metal surface close to the ignition switch. This could include a metal screw or the car's body (if your probe will reach that far).

With the key in the "run" position, touch the red positive probe to any of the metal connectors on the back of the ignition switch, opposite where each wire lead is connected.

This should give you a reading around the standard voltage for your battery, around 12 DC volts. If you have a reading close to this, your ignition switch is getting normal power.

A reading much lower than 12 volts means that your ignition switch isn't being appropriately powered, which is a sign that you have a faulty switch.

Test Spark Plugs

Another method involves using a test spark plug to check for a good spark when cranking.

Remove the ignition coil from one of your plugs and plug a test plug into the coil boot. Next, touch the metal end of the spark plug to a metal surface on your engine to ground the plug.

Now have a helper attempt to crank your vehicle, and watch the end of the spark plug.

If you see the plug sparking while the car is trying to crank, your ignition switch is good.

A lack of spark will indicate a faulty ignition switch.

Don't let your vehicle run if it does crank; it will misfire with the ignition coil off of the spark plug. Instead, remove the test plug and plug the coil boot back into the spark plug in your engine.

Test Ignition Switch For Continuity

Another effective method is to use your digital multimeter to test the ignition switch for electrical continuity.

Continuity is the reading of whether an electrical circuit has resistance, which indicates that the circuit is working correctly.

Set your multimeter to the resistance or ohm test setting to test this.

The resistance setting will look like an omega symbol if it doesn't have any other marking to indicate this setting.

With the steering wheel cover removed, locate the terminal connections on the back of the ignition switch. There are usually five terminals that correspond with each function of the switch.

Each of these terminals will have continuity with another terminal depending on the position of your key on the ignition switch.

The way to test each of these connections is complicated to explain, but if you have access to a service manual, it should explain which connectors to test at which switch position.

If you want a more straightforward explanation of this process in video form, a quick search on Youtube should bring up videos explaining this process in a way that's easy to follow.

How Do I Know If My Starter Or Ignition Switch Is Bad?

If you have tested the above methods for your ignition switch and all checks have passed the test, your problem may be the starter rather than the ignition switch.

You can use the same multimeter you tested your ignition switch with to test the voltage reading at your starter.

You should again set the multimeter to the 20 DC volt test setting.

With the key in the "run" position, ground your black test probe to a metal surface near your starter.

Touch the red test probe to the positive terminal where the battery wire is connected.

This reading should also be around 12 volts, indicating that the starter motor is getting power from the battery.

If your starter is getting power but isn't activating correctly, you may have a bad starter or starter solenoid.

Will A Bad Ignition Switch Drain A Battery?

The fact that the ignition switch directs power from your battery means that it can drain current from the battery if it isn't working correctly.

A faulty ignition system may not completely shut off, even after removing the key from the ignition cylinder.

This can slowly drain your battery over time without you realizing it's happening!

How Much Does It Cost To Replace Ignition Switch?

As with all vehicle repairs, the cost of ignition switch problems will depend on your vehicle and whether or not you repair yourself.

A car ignition switch usually costs less than $100 for the part itself, especially for older cars.

If you have the knowledge and tools to replace the switch, you can complete the repair for just the cost of the part.

If you need to have a mechanic replace the switch, the cost of labor and parts will make the repair more expensive, usually between $150 and $250, with all costs included.

Conclusion

The ignition system is essential to the function of your car since you can't drive anywhere if your car doesn't crank.

Thankfully, there are ways to get around having a bad ignition switch and keeping your car out on the road.