BMW Repair: Radio controls, radio works, volume knob

Question

My car radio function buttons on the radio and steering wheel aren't working, tried changing fuse 7 and 41 but they still don't work. First the entire radio didn't work but after changing fuse 7, the radio works but the buttons don't. Also the CD player repeatedly keeps trying to spit out the cd even after the car is off, worried that was going to drain my battery I took fuse 41 off and left it out.  The volume knob can be turned up or down but you cannot turn the radio off, also the volume controls work on the steering wheel only. The airbag light is not on. What can I do?

Answer
This kind of wiring problem is almost impossible to diagnosis remotely.  You've done a good job of determining what works and what doesn't.  

About the only thing I can suggest is to pull the radio and clean the connections with contact cleaner, but I don't think that's going to do much.

Without a good diagnosis, your next step is to start swapping parts.  If you have a friend with a similar model, you're in luck.  Otherwise, it gets expensive fast.