I found out this weekend that the idrive (assuming thats the media controller wheel thingy whatsit) actually runs on a ring network, with fibre-optic connectors. Apparently if anything in the chain gets damaged (headunit, navunit, bluetooth, CD changer, idrive wheel itself, etc, etc) it can cause the whole network to fail. Some right feck-tard must have decided on that topography when all other manufacturers are using a typical bus layout. A friend who told me this has learnt a lot over the past few weeks as a car he has interest in has this problem. It took a specialist about a day to find the reason the idrive wheel wasnt working right was because of a faulty bluetooth unit
Spot on mate!!