My E60 5 series has a rattle on the obc stalk with the small buttons rattling after the car has been standing in the sun or when travelling on a hot sunny day. Saw this guy in BMWCar Mag who had a 520d solve the problem. It seems to be a common problem on the E60/61's. What he did was also to cut a very thin piece of insulation tape and stick it onto the buttons between the buttons to stop them from rattling. It worked for him. Must still do it on my car but keep forgetting to do it. Must do it sommer now!!