Conventional Ignition Switch System: Acc

When the ignition switch is in the ACC position, the switch routes voltage through the ACC-designated circuit to the BCM  . When the BCM  detects voltage from the ACC-designated circuit, it activates the accessory delay relay (by providing ground to the coil side of the relay) and sends a message over the CAN  to other vehicle modules. This allows functionality of specific electrical systems without placing additional current drain on the battery from the powertrain electrical system when the vehicle is not running.