Recently mu wife purchased a 2003 Prius. The sticker on the car included $1900 for a Nav system. But when we test drove the car you got the "external device not connected" or something similar error when you hit the map button. The salesman said that ther must not be a Nav system and they would remove it from the price. There was even a Navigation booklet in the glovebox but the dealer kept it. When we got home we noticed that the bill of sale still said that the car had a Nav system. For the heck opf it I checked under the passenger seat and there is a box with a loading slot for a DVD. So my question is, do we really have the Nav system? I can't imagine any reason why they would install the box if it wasn't needed. Any info would be great. Thanks! Mike