July 1: So it begins. Don't worry, this is not in the correct legal jurisdiction!
Section 6 (System Wiring Diagrams): Radio
WARNING: This page is about a different car, the 2005 MINI Cooper. However, it is still accessible from the selected car via links, so may be relevant.
Fig 1: Base Radio Circuit, W/ Telephone Provisions
Fig 2: Base Radio Circuit, W/O Telephone Provisions