The screen is a bit on the crappy side of things. It can be operated independently of the navigation unit in the trunk of the car, but it requires a communication with microcontroller.
The communication protocol is uni-directional (screen is always receiver) and serial. It uses (or is usable with) 5V logic.
Pinout for the connector in back of the car:
1 - Red channel for RGB 2 - Green channel for RGB 3 - unknown, NC 4 - serial data 5 - remote control sensor (I believe it's output from IR receiver mounted in screen) 6 - Blue channel for RGB 7 - video ground (chassis ground too, I believe) 8 - Sync channel for RGB 9 - unknown, NC 10 - composite video input (75Ohm terminated).
Overview of the protocol: https://github.com/festlv/carpc/blob/master/avr-firmware/src/rti/rti.h
Implementation for AVR: https://github.com/festlv/carpc/blob/master/avr-firmware/src/rti/rti.c