Nissan Maxima BOSE radio no sound..here is what to do

1999 Nissan Maxima has a nice Bose radio, it powers up and responds to the buttons but it does not outputs sound. I take a look at the system and determine that each speaker has its own amplifier, four wires..12v, ground and two audio wires. I measure no voltage applied to the amplifier, I backfeed the connector with a fuse protected 12 from the battery and the BOSE system outputs sound as it should. I suspect a relay has failed, I am sure that I can make this work. The car is on the lift right now so I can not easily get to the area I suspect the relay to be...passenger kick panel area. Either way....I know I can easily make this work