...possibility is that the DIN connection on the Sirius tuner might be plugged into the pass-through input rather than the output to the HU. To clarify the connection I was referring to, there are two DIN connections on the tuner. One of these DIN connections goes from the tuner to the Kenwood receiver. The other is a connection that would connect to a separate Kenwood unit such as a CD changer to allow both devices to connect to the one DIN connection on the Kenwood receiver without using an adapter. If the pass-thru connection is connected to the receiver, then the signal will not reach the Kenwood receiver.