I had a problem the other day with the navigation instructions volume being too loud. While I was driving I had adjusted the radio volume a few times up and down, and somehow the nav instructions got bumped up in the process (became extremely loud). After a few minutes of trying to adjust the volume in the settings menu.. It finally hit me. The volume can only be adjusted on the unit "as" the instructions are being read (temporarily supersedes the radio volume). Kinda felt like a moron.. :shocked: