The Chevrolet Ignition Lock Cylinder and Switch is the safety device designed to help keep your vehicle from being taken by any unauthorized person. The ignition lock cylinder and switch is situated in the steering column of your Chevrolet so unless the correct key is put into it, the locking mechanism it contains will not release the lever which makes it possible for the steering wheel to turn.
The replacement of the Chevrolet ignition lock cylinder and switch does involve the disassembling of the steering wheel column. While the covers of the steering column do have to be removed, in most instances the two mounting bolts that hold the column securely to the dash only have to be loosened to gain access to the ignition lock cylinder and switch. If the bolts have to be removed, make sure the steering column is supported so the many electrical connections the Chevrolet steering column has on its interior are not stressed and improperly pulled loose.
It is highly unusual for the ignition cylinder lock and switch to be faulty if your vehicle will not start. If the locking mechanism will not disengage when the key is turned, the first thing to do is to apply a penetrating oil to the lock cylinder while giggling the steering wheel. If that does not free up the steering wheel, the steering wheel covers will have to be removed so access to the ignition cylinder lock cylinder and switch can be gained. The lock holding the steering wheel in place is at the bottom of the lock cylinder and should be inspected to see if that is the faulty component on your Chevrolet.