To replace an ignition lock cylinder, disconnect the battery, set the key to the accessories position, and use a paper clip to release the ignition lock cylinder. Replace the old lock cylinder with a new one, and reconnect the battery.
Purchase a new ignition lock cylinder that is compatible with the make and model of the vehicle, and disconnect the negative battery terminal with a wrench. Move the terminal to a location where it does not touch the battery. To remove the old ignition lock cylinder, turn the key to the accessories position. Locate the small hole under the key slot, and insert the end of a straightened-out paper clip straight into the pinhole until it meets resistance.
With the paper clip pressed firmly into the ignition release hole, turn the key to the off position, and pull the ignition lock cylinder to remove it. Take note of the position of the cylinder to ensure the new part is set in place properly. Remove the paper clip.
Place the key into the new ignition lock cylinder, and gently push the new cylinder into place. Turn the key to the accessories position then to the off position to secure the new ignition lock cylinder. Reconnect the battery terminal, and start the car to test the new part.