Hello I could use some help , i recently bought a 2011 ford edge sport sel 3.5 , well the lady i bought from had stated they have had problems off and on with the backup camera you can hear the radio and it will make the beeping noise when in reverse but the screen stays completely black , iv'e checked fuse 29 located inside of the vehicle it was good tried disconnecting battery for 10 or so min then reconnecting still nothing can anyone help or have any advice ? id greatly appreciate it.