Normal Operation
WARNING: This page is about a different car, the 2006 Mercury Milan, 2006 Lincoln Zephyr, and 2006 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.
When the key is inserted into the ignition cylinder, the key-in-ignition switch (part of the ignition switch) closes circuit CDC30 (BU/GY) to the instrument cluster, providing a voltage signal. The voltage input signals the instrument cluster that the key is inserted. Door ajar status is communicated to the instrument cluster from the smart junction box (SJB) through the communication area network (CAN). If the instrument cluster detects that the ignition lock cylinder is in the OFF or ACC position, the key is inserted in the ignition cylinder, and the SJB communicates to the instrument cluster that the driver door is ajar, the key-in-ignition warning chime sounds.