I had this problem for about 3 years. I had the haed unit replaced by the dealer, and that didn't fix it, but one day I discovered a work around. If you hit the panel on the passanger side of the stereo, from the side, it will reconnect and work. It seems like there is a known problem with the Bose system, where some connections get loose inside. By applying a little pressure, hitting it, not to hard, from the side, it falls back in place. A permanent fix is to take the head unit apart and do some soldering. Instructions on how to do that are on
http://www.nissanmurano.org.