I have successfully installed a backup camera in my '06 Tribeca. This thread and the posts at http://www.legacygt.com/forums/showt...148#post755148
were immensely helpful.
What I have learned is that the camera or video source must be plugged in to the Nav display WHEN IT IS BOOTING UP, and also the shield or common line to the video source must be grounded to the car. If either of these do not happen, then the NAV will not switch on the video when in reverse. As a matter of fact, if you just ground the lower left pin of the molex connector and boot the system up, the screen will go blank when in reverse because it is expecting a camera to be hooked up.
If anyone is interested in the connector on the back of the unit, go to www.molex.com
and search for 39-01-3042. That is the part number of the connector that plugs into the back of the NAV display.