Audio Systems: 93 Maxima Bose stereo trouble, bose system, bose stereo

Question
I had the head unit stolen out of my 93 Nissan Maxima bose system. None of
the chords were cut, and the head unit that was stolen was aftermarket, but for
some reason when I try and replace the unit with a new one, I get no audio to
my speakers. I tested the new stereo by connecting it to the power and an old
speaker that I had removed from a previous car, and it is sending out a signal.
Any idea how to get signal back to my speakers?

Answer
There may have been interface box(es) that were stolen as well.  These links should help you find what you need;
http://www.scosche.com/scosche_caraudio.aspx?CategoryID=229&ItemID=SLC4
http://www.peripheralelectronics.com/prodDetail.asp?strProductID=572&strCategory...
Metra's 70-1764 harness look promising also, but may still require a level matching device.