Not having a nav/video unit myself, I can't guarantee how well that would work, but yes, it should work. The ipod video headphone jack can actually be used to send video as well using a cable with a 1/8" stereo plug on one end and 3 RCA jacks on the other(although apple claims that you NEED their "special" cord to do this, when in reality you dont, you just have to plug your RCA's in in an odd manner, switching the red and yellow leads). The disadvantage being, it wont charge the ipod like that, you'd need a car charger for it. I'm not aware of any car stereo control units for video ipods that support video through the docking port, although I suppose you could use a universal home dock with some creativity.