Can I change from an 04 navi to an 07 just by changing the dvd unit under the passager seat?

I wish it were that simple! No, you need to change the Nav headunit too, change the wiring harnesses since the newer screen uses a different adapter...the list gies on and on, so the short answer is no, you cannot upgrade the nav without buying a new car.

Thanks for the quick reply.

Hi. I have 2007 GX 470 and DVD-Navi unit is acting up sometimes. How can I replace it? Or may be I can do something about it?

Thank you

You can do something. Take it to the dealer. Are you out of warranty already?

Unfortunately, No Warranty, due to high milage