the fiber optic network is a ring network. disconnect any device and you break the ring, and nothing works.... (bare minimum on i drive)
but if hte nav has a physical problem, it shouldnt affect th whole system (but it can)... when does the problem happen... when you are imputting data into navi in i drive or while being directed? does the radio go off when not using navi...
what is it like when this happens.. does it "glitch out"? do you get like a static beep from your speakers and everything kinda reboots? or is it like some one hit the volume knob and it just turned off and you have to turn it back on?