Update on the Parking Brake sensor:
I tore my dash apart for the umpteenth time to hunt for the Parking Brake sensor. I am getting like an Indy pit crew and can remove the NAV in less than 10 minutes now. Must force myself to slow down lest I end up with a $2,000 paper weight.
First I scavenged some old female socket-pin receptacles from some of my spare PC parts: I also build computers from scratch so had lots of eligible data cables laying around. Then I unplugged all the cables from the NAV, examined the connector which I suspected of containing the Parking Brake sensor, and lo and behold it does contain a pin but no wire in the connector. I disassembled the connector and inserted numerous pin sockets but none of them fit just right - dang socket is a unique size. So I selected one that was big enough to fit the pin but small enough to slip through the assembled connector. Plugged the connector in, fed the pin socket in by hand with tweezers, and bingo it connected. Reinstalled the NAV and fired it up..... and.... SUCCESS!!!
Er... sort of... the diagnositc menus now confirm I can toggle the Parking Brake sensor on or off, however this has no bearing on the NAV functions being enabled or disabled while in motion. All was not lost, though, as my testing also revealed an unused connector on the back of the NAV which I believe is for the rear-seat DVD player. If this is true then I just need to find the pin-out for that connector and I can now use the Parking Brake sensor to enable even more functions on the NAV such as a video input without the crappy "check surroundings" disclaimer.
The testing continues for a permanent speed pulse bypass but I am getting closer by the day and finding even more functions every step of the way. So close but yet so far...