The multi function switch is the combination headlight/turn signal/etc on the steering column. Replacing this switch is a royal pain in the butt at best. Without the technical knowledge to handle tasks such as disarming the air bags, etc you can end up getting hurt or hurting someone doing this job yourself.

Without a good wiring diagram, digital volt meters, etc, and a good understanding of how the system functions, you are better off letting a good repair shop or a dealer service deartment deal with this one.