I'm old and the GPS screen in my PRO4X is too small for me to see...If I buy a large screen, how do I project the data from my in-car GPS unit?
Short version of the above LOL: you can't.I don't know the specifics of the Frontier's stereo/nav system, but I am a computer engineer for what that's worth.
Unless there's some kind of video output on the back of the OEM head unit, I think the short answer is "you don't". Even if you somehow manage to hook up a different screen, there are a whole lot of things that will probably go wrong if the software that powers the display wasn't designed with the specific characteristics of the new display in mind. My experience with automotive software and embedded systems in general is that they are almost never designed to accommodate things like this because it is much faster (and therefore cheaper) to write code that simply assumes things that you "know" to be true (e.g., the display's size and resolution).