I have a 2006 XK8 with the original factory stereo and navigation unit. My question is..is it possible to install an aftermarket stereo and aftermarket amplifier and still have the original navigation system to function ?
My hope is to install an aftermarket stereo and amp and get the Auxillary video
set up from the Jag Wrangler that will hopefully allow me to play video from my aftermarket DVD player onto the original navigation screen while still retaining the functionality of the navigation system.
Is this possible to have the original factory navigation still function after the original factory radio/cassette player has been removed ? Has anyone here sucessfully done something like this ?

 

I do not know, if you have the Alpine-HU and Nav in your 2006 model. If your car has the same Alpine-unit as mine 2004MY, you can't use the nav without the head-unit. Both are connected & communicate over a serial 2-wire databus (Alpine AiNet), also the stereo audio-signal is going over the AiNet-Cable - a ~6mm black cable with special connectors. You can see it in the trunk beetween CD-Changer, nav-unit, Audio-Amp (if fitted). The nav gets commands from the HU, e.g. if one of the nav-buttons was pressed. Also the audio-signal for the mono nav-voice is routed by commands from another databus - AFAIK Ford ACP.

But what you CAN do with this system, exchange the aged nav-unit with another more modern gps with a RGB-output (video signal with much better quality as the often used composite-output), because of the screen itself can be used without the HU, as long as you put a +12V Level as an 'enable signal' on one of the screen's interface-leads ( eg at the connector in the trunk ). I've done this on my 2004MY XKR. see: Wiring/Connection of XKR-Nav-Screen to aftermarket equipment - the 1000st - Jaguar Forums - Jaguar Enthusiasts Forum
IIRC white-xkr offers a adapter-loom for the RGB-connection to aftermarket units.
The culprit is, that the buttons beside the screen will get useless without the HU.
To adress this for myself, i've built a µcontroller-based interface to convert the AiNet-commands to USB-Keyboard keystrokes for a wp9900 gps-unit. But due to heavy stress with my business over the last year, the firmware is not complete until now.

Greetings from the ruhrgebiet...

Wolf