[MikeGMT]

If it is the previous generation of Sensus it may be a setting in the menu, there is a option to select Map Mode and Compass Direction. If you go into Navigation Map Options you can select how the map is shown. 'North Up' and the map always has North at the top, and the car symbol (Blue Triangle) moves on the screen depending on direction of travel, if you are going West the triangle will move across the screen to the left, while the map remains pointing North. If Map Heading Up is selected, then the car symbol always travels up the screen and the map moves around depending on direction of travel.