Trace the wire from the ignition switch to the main wiring harness connector and disconnect it. Using an ohmmeter or self-powered test light along with the accompanying diagrams, check for continuity between the indicated switch terminals with the switch in each of the indicated positions. If the continuity isn't as specified, replace the switch. Disconnect the cable from the negative terminal of the battery, ensuring you have the correct activation code for the stereo's anti-theft system if applicable. Place the ignition key in the ACC position, then remove the steering wheel, followed by the steering column cover, and then the combination switch from the steering column. Unplug the ignition switch wiring harness connectors and detach the switch retaining screw to remove the ignition switch assembly from the steering column. For the lock cylinder, detach the illumination ring if equipped, then use a small screwdriver or punch to depress the lock cylinder retaining pin and pull straight out to remove the assembly. To install the lock cylinder, depress the retaining pin and guide it into the steering column housing until the pin extends back into the locating hole. Complete the installation by reversing the removal steps.