most the time navagation DVD player will only play DVD's with the engine off key on and parking brake up. That is how the 350Z navi player works. You just have to find the player some times its somewhere like side of the console or behind the seat. or trunk. 2004 Nissan Maxima DVD player us under the radio inside the dash accessable after a cover is removed. Nissan Titan truck under the passengers seat Watch the road not the Movie! Just had to say that> When you reload the Navi softwear disk do it outside so your GPS antennia can locate where the car is again.