Signs of a Failing Ignition Lock Cylinder

Mia Bevacqua
January 14, 2019

ignition lock cylinder

Your car’s ignition lock cylinder is kind of like the door to your home: You’ll need the right key to get it to work.

Inside, the cylinder is similar to a household lock, as well. When the key is inserted, it pushes down on a series of spring-loaded pins, allowing them to line up with a track called a shear line. When everything is aligned, you can turn the lock cylinder.

» LEARN MORE: Find a trustworthy car repair shop near you

But, while a household lock turns a bolt to unlock the door, an ignition lock cylinder rotates the vehicle’s ignition switch. This lets you start the car or turn on the accessories, like the stereo, when the car isn’t running.

The ignition lock cylinder and ignition switch are not the same thing. The lock cylinder is the mechanical tumbler your key slides into; the switch is the electrical portion that sends power to the vehicle. On many cars, these are two separate components that can be repaired individually.

Signs of a failed lock cylinder

These are the most common symptoms associated with a failed ignition lock cylinder:

  • Key won’t turn: By far, this is the most common sign of a failed lock cylinder. The problem usually happens due to the pins inside the tumbler wearing out over time.
  • Key is difficult to turn: When an ignition cylinder is worn and beginning to fail, the key may be difficult to turn. Often, it must be jiggled around or otherwise fiddled with to rotate.
  • Anti-theft warning light is on: If the lock cylinder is part of the anti-theft system (often the case with older General Motors vehicles), and the cylinder’s internal contacts fail, a warning light may appear on the dash.

» GET AN ESTIMATE: Learn how much a new ignition lock cylinder should cost

How to fix the problem

If you’re having problems turning the ignition lock cylinder, first check the key for wear and try using a spare, if you have one. A new key may be all you need.

Some people have been able to finesse difficult lock cylinders with graphite or WD-40. But in most cases, these solutions don’t work for very long — if they work at all.

Replacement is the only real cure for a worn or failed ignition lock cylinder. This is a job best left to a professional mechanic because, on many vehicles, the airbag system must be disabled before tearing into the steering column for replacement.

Mia Bevacqua

About the Author

Mia Bevacqua is an automotive expert with ASE Master, L1, L2 and L3 Advanced Level Specialist certification. With 13-plus years of experience in the field, she applies her skills toward writing, consulting and automotive software engineering.

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