Ok,removed sat nav unit and it's mounting bracket from the Tourer. Sat nav unit bone dry but water has been inside it at some point,see pic.
Sat nav unit had not been apart before by the looks of it as I had to cut the factory seal to get top and bottom covers off of it to look inside.
As you can see,corner of printed circuit board inside don't look pretty. Might be able to clean it up but some of the joints look corroded.
Anyway,even with the sat nav unit removed Highline still not working.
Only moisture I could find around where sat nav unit lives was when I lifted up a thin rubber type mat under where it's bracket is. Maybe it's seeping in from that vent thing on wing in pic two. Can't see any history of water leaks/marks higher up though.
Will unbolt and remove other two Highline units in spare wheel well when I get time and see if they have any moisture in them
