Thought I posted this today but can't find it? So I'll try again!!!

There must be some hi tech guys in this forum. I have a 2003 S8 that comes standard with Tire pressure and GPS (unit in trunk) systems. I have no display of these on the dash display. Does anyone know the component that drives the display or what I need to check or service to make this work. Or, where I can go to for specific information on this? I would really appreciate some advice.
TNX
Maxx