Big-T

OK. I'm stuck. What I've gotten so far is confusing me . I have a 1998 750IL, and the TV only receives the audio for the various channels (I can tell that it is receiving the different channels by the audio). I only see a black screen however. Now, from what I can see, the car is already wired and connected for the TV. That's without taking apart the NAV area to look at the back of it. Also, I read that on the early 1998 7 series, some came with the TV wired but the dealers disconnected the VIDEO part. Since I bout the car used, I have no way of telling if this is something wrong with the TV, or that the EXECUTIVE who owned the car before me had it wired, but then the dealer disconnected it? I'm really unclear. Can someon please shed some light on this matter, and if possible, tell me what to look for in order to truly confirm it IS wired properly, and what to check for to get this video part (which seems simple is everything else works) to come through. BIG-T...Where are you buddy!!!!! Please HELP!!!