Head unit kaput?

[04X5-4.4]

Wives navi screen and radio stopped working the other day. The screen has been coming and going for some time now, but now no sound, and a full time blank screen (it does have power). I pulled the unit out to have a look, and noticed this third harness (small black one in the middle) wasn't connected to anything, but didn't see an obvious place it might go. Not sure if its even supposed to be connected to anything, and if so, where it goes. My guess is the unit is shot. If thats the case, does anyone have any suggestions on where to find a new one, or perhaps get this one fixed. Thanks in advance for any input or suggestions...