Symptoms of a Failing Ignition Switch (2024)

How Does an Ignition Switch Work?

The ignition switch operates like any other switch does mechanically – when the contacts change position, it directs power to the circuit or circuits that are selected and cuts power to those that aren’t selected. There are commonly four positions to an ignition switch:

• Off. In the OFF position, your vehicle is parked and the engine isn’t running. The ignition-controlled electrical systems are off, and only non-ignition related circuits like the lights continue to operate.
• Accessory. In the accessory or ACC position, systems like infotainment and power windows are often enabled, letting you use limited functions while you’re in the car without the engine running.
• On. When the ignition is in the ON position, systems like the HVAC controls and dash instruments are on. Essentially, any systems that are enabled when the engine is running are on at this point, and it’s the position your ignition needs to be in when the car is running also.
• Start. The START position is only momentarily powered when the engine is cranking over. This position powers the starter circuit.

The power for all of these circuits does not flow through the ignition switch. Rather, it’s a low current that’s used, and they operate relays to make these functions work.

Another important aspect of many ignition switches is the anti-theft or immobilizer system. ‘Chipped’ or programmable keys broadcast an RFID, and only an ignition switch that can read the corresponding ID will allow the key to start the car.

Symptoms of a Failing Ignition Switch

The ignition switch lasts for thousands and thousands of engine starts and key cycles, but there may come a time when it fails. If it does, you’ll encounter symptoms such as these:

• Key is hard or impossible to turn in the ignition. If you’re unable to turn the key in the cylinder smoothly, it might be either the cylinder itself or the switch behind it that’s jammed or binding.
• Engine won’t crank. If the electrical contacts inside the switch have failed, turning the key to crank the engine might not result in any response at all.
• Engine starts and stalls. If the engine starts and stalls immediately, it could be an issue with the anti-theft system. It allows the engine to start but doesn’t recognize a valid key so it shuts the engine off again.
• Electrical issues or inoperative accessories. Sometimes, a faulty ignition switch can prevent the accessories and auxiliary functions to stop working since their circuits aren’t receiving a signal to power up.
• Stalling when driving. A faulty ignition switch can lose an electrical connection while you drive, such as going over rough roads or bumps or turning the steering wheel.

Unfortunately, these ignition switch symptoms can sometimes be tricky to duplicate and diagnose. They can begin as intermittent concerns and slowly progress.

Causes of a Failing Ignition Switch

It’s no surprise that the most common cause of a bad ignition switch is wear and tear. The more ignition key cycles performed, the higher the likelihood of an ignition switch failure. Also, causes can include:

• Corrosion on the terminals
• Bad wiring
• Loose connections
• Electrical surges or shorts
• Physical damage from an attempted theft

Preventing Ignition Switch Problems

The ignition switch is tucked away, out of sight, so there’s not much you can do for preventative maintenance. However, since wear and tear is a leading cause of failure, there are two suggestions that can help in this area.

First, try to reduce any instances of key cycles that aren’t necessary. That’s a tall order since most key cycles are intentional and purposeful, but it can reduce wear on the switch.

Secondly and most importantly, remove clutter from your keychain. Heavy keychains and trinkets that dangle and sway from your keys can add strain to the cylinder and the switch, causing it to fail sooner. If possible, keep only your car key and fob on the keychain and your other keys separate.

For ignition switches, cylinders, and other parts you need to fix your vehicle, AutoZone is the right choice. Find everything you want in one place from top brands like Duralast. You can get the parts you need at your local AutoZone Store. If the job is too big for you, seek out one of our Preferred Shops to help you do the job.

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