Looks like they moved that fuse box to a more convienent location, which is good, and good to know.
When I said "sending unit" I meant the GPS Antenna/Receiver because it would have a position (Latitude/Longitude) output. The Lat/Long data then has to be coverted by some sort of map processing unit for the display to an X/Y system, i.e., so many pixels over and so many pixels down. Since yours seems to be stuck in the Mississippi River, I'm theorizing that your GPS Antenna/Reciever is the problem.
However, the GPS Antenna/Reciever and the map processing unit may be built into the same physical box and share a common fuse. And since this is a system that wouldn't be expected to fail very often, the fuse may be in the secondary fuse box, located in the trunk next to the battery.