the PDC module is located under the spare tire in the battery compartment, next to the BM radio, and it has 3 plugs. The middle plug has multiple pins, and the Pin #7 supplies signal voltage to the green light in the front of the car in the button module in the center console. When PDC is engaged, the green light on the PDC button lights up via Pin #7 on the middle plug - the voltage and amperage are very low, and that pin supplies (+) voltage.

If you will take that (+) signal and convert it via a low voltage/low amperage relay to a (-) ground, and apply that (-) signal to the wire for the reverse signal, you will have the reverse camera engaging everytime when the PDC is engaged. It also will give you an ability to activate the camera by pressing the PDC button on the center console switch panel (module A169).

there is a drawing of that connection somewhere on this forum, rather easy to accomplish if you have a factory PDC - only one tap to pin 7, one relay and reliable ground.
So, if you tap into Pin #7 on the middle plug on the PDC module, apply that signal to a coil of a relay, and have relay contact apply ground to the reverse camera wire off the TV module, you are done...