Nissan Primera 2.0 T Spec - Sat Nav broken?

I seem to have the same problem with my Nissan TSpec as most others posting on this site. The Sat Nav and and hence all electronics on the car jsut don't work. It has been up the creek for about 6 months at least now and like others, it might work a little but only when it feels like it. I was going to take it to the dealer and see what could be done, but if anyone has found a solution I would rather save the money. I also had to have the automatic transimission replaced at a cost of £1200.00 so for a Japenese car I seem to have the most dud one in creation! Any help on the Sat Nav problem would be very helpful