Name Brand Speakers (NBS) relay

The NBS relay operates through the vehicle bus interface between the radio and the FCM. When the radio is turned on, the radio sends a PCI Bus message to the FCM. The NBS relay is then powered on through low side control on pin 11 of the FCM. The relay supplies power to the amplified speaker, and ground is supplied through the radio. This circuit is electronically controlled and continuously monitored for malfunctions.