2002 BMW E39 5-Series Car Radio Audio Stereo Wiring Jul 08, 20142002 BMW E39 5-Series Car Radio Audio Stereo Wiring Diagram Colors July 8, 2014 CarAudioWiringDiagram 1 Comment Here is the stereo radio wiring information for your 2002 BMW 5-Series E39 525i, 528i, 530i, 540i and M5 with the standard, symphony, or Bose systems.[PDF] analog and digital systems inc., BMW 5-Series (E39) Audio BMW 5-Series (E39) system upgrades Correct speaker level wiring diagram for interfacing with factory head units. Use only positive (+) speaker wires. Tape off negative (-) speaker wires. Connect “+” speaker wires to RCA center pin conductors. Tie shields (audio return) together and ground to case of radio at back of radio. Repeat for 4 channel system.