Originally Posted by UCrewX5

The radio module on an X5 with navigation is located down in the spare tire compartment, behind the battery.

Here's the bad news. The radio module in a 2001 X5 doesn't support AUX. I replaced my radio module with one from a 2003 X5. To do so you also need to have a conversion harness, as the 2001 radio module uses round pin connectors and the newer radio module uses a flat pin connector. See http://www.xoutpost.com/articles/x5/s...formation.html