Normal Operation - MKZ

WARNING: This page is about a different car, the 2011 Mercury Milan, 2011 Lincoln MKZ, and 2011 Ford Fusion. However, it is still accessible from the selected car via links, so may be relevant.

The Smart Junction Box (SJB) supplies voltage and ground to all the passenger door lock actuators by controlling the lock all and unlock all relays. The Driver Door Module (DDM) supplies voltage and ground only to the driver door lock actuator. The SJB receives inputs from the RH door lock control switch, keyless entry keypad, and the Remote Keyless Entry (RKE) transmitter. The DDM only receives input from the LH door lock control switch. Both modules share the information obtained from the inputs over the Medium Speed Controller Area Network (MS-CAN). Upon a lock request, the SJB supplies voltage on the passenger door lock circuit and ground on the passenger door unlock circuit, and the DDM supplies voltage on the driver door lock circuit and ground on the driver door unlock circuit. Upon an unlock request, the voltage and ground are reversed on the previously listed circuits. When the door lock and unlock relays are not energized they are connected to ground. A dedicated SJB ground circuit is provided only for the lock and unlock relays.