crkelly

Hi All, I just stumbled across this thread from an ih8mud link and decided chime in with some thoughts. It seems the problem people are having is that when the front screen turns to Nav, it deactivates the rear screen. I have a few questions: 1) The rear (headrest or other) screen(s) go blank when this happens, right? They don't start displaying Nav content? 2) Does the Nav output feed through the DVD? Or do they both go straight to the head unit? Do they have separate inputs on the back of the head unit? Just thinking out loud here, comments welcome... I was thinking that maybe, if the Nav fed through the DVD changer, then there might be only one video input to the back of the head unit, with the DVD changer making the determination of what source to pass forward to the head unit. If this is the case, then there would be no way (that I can think of) to display the DVD video on the rear screens as long as the Nav is displaying on the front. However, also if this was the case, I would also expect that the Nav video *would* be shown on the rear screens, rather than them just going blank. It doesn't sound like this is what's happening, though (which may be a good thing). Alternately, if the DVD and Nav video signals are fed separately into the head unit, then something in the head unit is causing the switch over between DVD and Nav. There *could* be a circuit in the head unit that says if there is a signal on the DVD input, always display it, otherwise, show the Nav. (I don't know why they simply wouldn't have a switch feature that allows you to select one or the other by choice, but this could also explain how they deactivate the DVD video signal when the vehicle is moving - rather than switching things to Nav in the head unit, turn off the DVD video output and have it switch over automatically.) This would mean the head unit would have to be feeding a signal back to the DVD changer telling it to activate the video output or not. In that case, if you could find that signal line, you might be able to interrupt it or falsify the signal to cause the DVD video to not turn off. But then, if the head unit uses the presence of that video signal to determine when to display Nav and when to show DVD, causing it to be always on would remove your ability to switch over to Nav. *That* would then require another switch of some sort to interupt the DVD video input into the head unit. But, assuming my assumptions are correct, that could be a solution. Find a way to override the signal from head to changer to keep it outputting the video, then install a switch to cut of the video signal into the head unit, after the point where you splice off from that signal to go to rear screens. Colin