Description: A switch, typically located in the steering column or vehicle dashboard behind the ignition lock cylinder, used to power on and start the vehicle. Used w/ a tradition vehicle key. Fits A4, Q5, S4, S5, SQ5 Electrical Components, w/s-Type. S5. SQ5. SWITCHES & Controls, w/S-Line or S. S5. SQ5. Electrical Components, w/ s-Type. Switches & Controls, w/ s-Line or s.