I have a 2001 QX4 that I purchased used but have put in A LOT of money to get in great shape. However, now the Nav system has started to ask for a navigational disc, even when it is installed. I do not care about the Nav system, but when it asks for the disc, I am unable to see the A/C controls. It does resolve within about 2-3 minutes, but I am concerned at some point, it won't. With having spent well over $13,000 in repairs I do not want to get rid of it, as I love it, but if I have to replace the unit, I so far have not found one. I have to be able to see what I am doing with the HVAC controls. Any thoughts?