Originally Posted by nox1s
It's probably the same as the GPS.. it uses GPS to determine speed. To watch dvds/use the navigation with most GPS units you just simply ground the parking brake wire.
From what I can tell that's the gist of it. The speed sensor is for the GPS to A. determine speed to calculate time of travel B. there's an actual speedo display (as well as a g-force meter) C. to turn off the DVD player
There is a way around the DVD player cut off however... I've just never cared enough to do it.
There's a D.I.Y. on this forum:
AVIC411.com