Ignition Switch: Notes

WARNING: This page is about a different car, the 2014 Lincoln MKX and 2014 Ford Edge. However, it is still accessible from the selected car via links, so may be relevant.

The ignition switch is controlled by the ignition lock cylinder and key. The ignition lock cylinder and ignition switch are connected mechanically, turning the lock cylinder places the switch into the desired position. The available ignition switch positions are:

OFF
ACC
RUN
START

When placed in any position other than OFF, the ignition switch provides voltage inputs to the Body Control Module (BCM). When placed in the START position, the ignition switch also provides a voltage input to the PCM. The BCM distributes this voltage to other modules and vehicle systems through the run/start bus. The microprocessor internal to the BCM broadcasts an ignition mode network message over the Medium Speed Controller Area Network (MS-CAN) and High Speed Controller Area Network (HS-CAN).