VDC is Vehicle Dynamic Control.. its a stability control system that automatically applies any combination of the four brakes to save the car from an uncontrolled skid. The nav uses that system to detect wheel rotation and add more detail to motion detection. This way your nav will still work even when no sats are visible - in parking garages, under heavy foliage, long tunnels, whatever the reason.
I've been thinking, and its possible that system is even tied to the tire pressure monitoring system, yet something else you'd have to try to retrofit if you don't already have it.
Then you have your system information screen. When you have nav, the display screen is an LCD, not a series of LEDs. You'd have to rip out the controller for your non-LCD screen and replace it with the new system information controller. Finally, as I mentioned before, you'd have to interface the nav controller with a point on the circuit board of the radio head unit that allows the nav to lower the volume of the radio/cd and send its speech output to the head unit. Your head unit may not even have the circuitry included to support that function.
So if you can identify (and reach) the components for the VDC, possibly the TPMS, the screen, the nav system, the nav dvd, the faceplate and stereo headunit, you may be able to staple them together and get them to work. Now you see why there are two other projects out there.. one to relocate the non-nav screen and replace it with a new 7" LCD connected to a PC, and another to decode the signals that fire the LED segments and translate them into a serial stream that can be sent to a carputer and processed for display on (again) a new 7" LCD connected to it.
Its a huge undertaking that would cost 10x or more the cost of an add-on gps or even the voice-only VCom mentioned here.
There are far too many interconnected components you'd need to install before the nav will work. Hardly worth the effort, if it can be done at all, IMHO.
