"THIS TECHNICAL BULLETIN PROVIDES A PROCEDURE TO CONTACT ONSTAR FOR HARD MUTE REQUEST TO CORRECT A CUSTOMER CONCERN WHEN THE RADIO IS ON, IT DOES NOT MUTE ENOUGH WHEN THE ONSTAR® TURN-BY-TURN NAVIGATION DIRECTIONS ARE ANNOUNCED DUE TO CUSTOMER IMPROPERLY SETTING THE RADIO VOLUME HIGH ENOUGH WHEN THE TURN-BY-TURN NAVIGATION MESSAGES ARE PLAYED. "