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Mounted to the steering column behind the ignition cylinder is the ignition switch. This part is responsible for activating nearly all of the electrical systems onboard your vehicle. When the switch fails, you’ll notice one or more problems that you’ll want to address right away.

Symptoms of a Bad Ignition Switch

Ignition switch problems can range from flickering interior lights to something more severe, such as a no-start condition from your vehicle. If you notice one or more of the symptoms below, it may be time to have your ignition switch checked by a professional.

starting the engine of a car
Ignition switch problems can range from flickering interior lights to something more severe, such as a no-start condition from your vehicle.

Engine Won’t Start

A bad ignition switch won’t be able to supply power to the starter motor, ignition system, and other engine controls, preventing the engine from starting. Keep in mind, however, that engine issues may also be caused by other electrical and mechanical problems, such as a dead battery or a faulty starter solenoid. To be sure, it’s best to consult a certified mechanic for an accurate diagnosis.

Vehicle Starts and Suddenly Stalls

In some cases, a faulty ignition switch will still allow your vehicle to start. However, the switch may only provide momentary power to the fuel pump and ignition system, eventually causing your vehicle to stall.

Ignition switch issues may also prevent you from restarting your vehicle due to worn-out ignition contacts, which have become more sensitive to heat and vibration.

Intermittent Loss of Lighting and Other Accessories

A defective ignition switch may cause your vehicle’s interior lights, dashboard lights, and other accessories to turn off momentarily.

Silent Starter Motor

A silent starter motor can indicate a bad ignition switch, but if you experience that, put the transmission in neutral and try again to see if there’s a problem with the neutral safety switch. However, if you hear any clicking sounds from the motor, you may be dealing with something other than an ignition switch problem.

Difficulty Turning the Key

A stuck key is another symptom of a defective ignition switch, which may leave the engine running even after it is removed. Usually, though, this kind of issue is more related to the ignition lock cylinder than the electrical part of the switch.

How the Ignition Switch Works

Your vehicle’s ignition switch has four positions that activate different systems:

Lock/Off

The lock/off position cuts off power from all circuits and locks the steering wheel. For automatic transmission vehicles, this position also locks the transmission gear.

Accessory

This position activates accessories, such as the radio, dashboard lights, and center console.

Run

The ignition switch’s third position powers the vehicle’s engine controls and other circuits except for the starter motor.

Start

The start position activates the starter motor and engine controls and allows the driver to crank the engine.

What Causes Ignition Switch Problems?

There are several reasons why your vehicle’s ignition switch may fail. Some of these include broken springs, worn ignition switch contacts, and temperature problems, which may prevent you from even getting your vehicle out of the garage. But if you do manage to get your engine running while having a defective ignition switch, it’ll most likely shut off while you’re driving.

Our Advice

A thorough diagnosis must be made to ensure that your vehicle is in need of an ignition switch replacement. An ignition switch replacement can cost you anywhere between $20 and $90 on parts and another $60 to $100 on labor. Costs may vary depending on your specific vehicle model as well as your location.

Keep in mind that installing a new ignition switch may require you to disable the steering column, which may deploy the vehicle’s airbags if done incorrectly. Some vehicles also require removing the air conditioning ducts.

To be safe, have a certified mechanic do it instead. Failure to replace a faulty ignition switch may leave you stranded in the middle of the road or cause your ride to stall in traffic, which is dangerous not only for you but for other drivers as well.

Various Configurations of the Ignition Switch and Lock Cylinder

The ignition key cylinder is connected to the ignition switch, which may be part of the key lock cylinder, but more often is mounted away from it and is operated by mechanical linkage. Some switches are mounted in line with the lock cylinder so that as the cylinder is turned, the switch rotates on the same axis.

Older Fords have a steel rod leading from the lock cylinder down to the switch where it’s mounted on the column. Some have plastic gears driving links that slide through channels in the steering column to operate the actual electric part of the switch, which is responsible for activating nearly all of the electrical systems onboard your vehicle. In extreme cases, the ignition switch, if it fails in certain ways, can set fire to the vehicle.

ford ignition switch
Older systems had some fairly heavy wires traveling through a rather robust ignition switch designed to carry a fair amount of current, but those switches could still fail like this Ford ignition switch. | Image Source: Richard McCuistian

More modern ignition switches tend to activate electronic modules, which in turn use relays to carry the heavy current that once traveled through the ignition switch (see 2019 Toyota schematic shown). Ignition switches don’t usually fail if they’re not carrying heavy loads.

2019 toyota relay schematic
2019 Toyota schematic showing relays that carry the heavy current that traveled through the ignition switch | Image Source: Richard McCuistian

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Any information provided on this Website is for informational purposes only and is not intended to replace consultation with a professional mechanic. The accuracy and timeliness of the information may change from the time of publication.

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