NTG1 with green Fakra input...where is the mux?



I am asking for help on any info available on location of the internal video mux circuit on this early NTG1 (pn 211 827 2542, US with DVD capable drive and 25 pin output connector)in my E320.
My plan is to open the unit, locate where the video is muxed(between internal and the rear Fakra connector) lift couple traces/skywire in a simple control circuit and have external control of what the unit actually displays(without the unit "noticing").
So...does anybody have a schematic of this part of the circuit or any info at all?
Any help greatly appreciated, and I will donate the control board that I will come up with.(I will make a few)
Also, if anybody has a junked NTG1 "guts", working or not, I am interested(must be provisioned for the green Fakra input), would rather practice before surgery.
Thank you,
Note: I am aware of the "intercept the LCD control" solutions like the Car-Concepts boxes. I only need one input, and want to use the Fakra already there that routes composite TV video somewhere inside!


