2005 A6 4.2

Nav stopped working on a long trip.
Took it to Audi who said antenna had a short in it. Not being able to quote a price and being Audi I decided no way.
I took the head liner apart, found the antenna cable was Open not shorted and replaced it.
Nav still isn't working. You can operate it just fine but it won't navigate. In other words it will tell me my work is 1400 hundred miles from my house. Shows me in NM somewhere. I am in TN.
Anyone have any ideas or suggestions. I want my nav back.

Question: Does anyone know what the little box is the antenna cable is plugged into under the roof liner? Can that be bad and be replaced?

 

Well...update:

Well...update anyway.
The problem is looking like it's the fin on top. I have my 5 volts (assuming that's correct) out of my antenna wire. So it's after that which only leaves the fin or connection to it.

Does anyone know how to get that off?