I have a 2009 G37x sport coupe and the rear-view / back-up camera has not worked since I got the car. I looked through the "backup camera definitely stopped working today" thread and the youtube video.

Here are the symptoms:

When simply reversing, the nav screen says "remember to look back" along the bottom banner and the rear-view camera view is black and there are no guide-lines.

When in the diagnostic screen, the reverse sensor toggles on/off properly.
When in the camera diagnostic screen, the camera display is black, and there are no guidelines.
I tried changing guide-lines but the guidelines do not appear, I went through all 7 options.
When in the sensor diagnostic screen, the steering sensor remains in the OFF position.

Guys, how else can I further diagnose the camera? I'd like to think that it is a faulty camera unit but why are there also no guide-lines?