King said:
Just don't get it! I have a new MKIV computer with a new 02/2004 NAV DVD disc and it keeps giving me wrong directions every one out of three times. Then it figures out where I am and tells me to make a legal U turn half the time! WTF is going on??
It could be one of a number of things. First, are the directions it is giving you correct, just really dumb (can you get where you're going with the directions)? If so, you're just running into the computer's idea of "optimal routing" - if you ask for "shortest distance" routing, it will give you the shortest route, even if there are lots of turns and minor roads.
Next, make sure you have good satellite signal - go to the "Settings" screen and press and hold the "Menu" button until you get into diagnostic mode. Then select GPS / GPS Status and see a screen similar to this one:
If you don't have a known position (3D/7 in the above image, could also be any other number or 2D/number) then you aren't getting a good GPS signal and your NAV is working off the inertial guidance, where errors will accumulate and it will eventually think you're on the wrong road. Once you correct the GPS problem, things should settle down.
Lastly, if you're in an area with road construction, it can get confused. Going up to the Bavarian Show & Shine last weekend, I was on the interstate where bridge construction moved my lane onto the other side of the highway. The NAV decided I was on a local road parallel to the interstate and said "in 100 feet, turn right at the traffic circle" which was rather confusing...