H3 Navigation Questions

[Chaugar]

Someone may be able to elaborate on this or explain it better. I have an eclipse system in my F-150. I use to have to park it, depress the emergency brake in order to use the Nav. I had one of the installers at a ford dealer ground the system to the frame? instead of the park brake, and now I have full acess to all Nav functions while driving. Of course it's safer for the passenger to operate it while you are driving. The passenger can even watch a movie while the vehicle is in motion. Cool!