I know about holding 3 and 6 for a basic test mode. Tho i remember from years ago there was another Debug mode of some kind that had a couple additional features. It had a sequence - getting into address book, entering a certain name, then hitting a hidden button somewhere - or something like that. Does anyone have anything on that? I know these units are old and could be easily upgraded, but we have two 2007 GT500s that are identical - his/hers - and we're keeping the original units. One unit had gone bad - and we had to replace with a Ford Edge unit, so it doesn't have the 'convertible'