From: Billo billo_at_unofficialbmw.com
Subject:  Stereo Wiring

1980's era BMWs E23?, E24, E26, E28, E30

BETWEEN HEAD UNIT AND BOOSTER AMP
  Yellow/Red - Left Front Channel
  Yellow/Black - Left Rear Channel
  Blue/Red - Right Front Channel
  Blue/Black - Right Rear Channel
  Yellow/Brown - Left Channel Ground at Amp End Only
  Blue/Brown - Right Channel Ground at Amp End Only
  Brown - All Channel Ground at Head End Only
(note that the all of the grounds are spliced together within the wiring harness - the 

system uses a common ground between the head and the amplifer)
  White - 12V Switched (to turn amplifier ON when head unit ON, also runs to power antenna)

BETWEEN AMP AND SPEAKERS
  Pair: Black/White and Black/Brown - Right Rear Speakers
  Pair: Grey/White and Grey/Brown - Right Front Speakers
  Pair: Black/Red and Black/Purple - Left Rear Speakers
  Pair: Grey/Red and Grey Purple - Left Front Speakers
  (note that the wires highlighted in red above all run to the crossover side of 
   the midrange drivers, you'll want to know this to keep all your speakers in 
   phase - make sure all of your speaker (+)s go to these wires)
  (also note that the speaker circuits DO NOT use a common ground when they leave the
   booster amp)

OTHER WIRES
  Red/Black - 12V Battery Power (via 30 amp fuse in fusebox according to Bentley)
  Brown - Power Ground

(Note from Dale: '80's era cars had external amplifier and non-external amplifier systems. Be sure to 
 identify the type you have.  All the premium stereo's had external amplifiers.)



1990's era BMWs, E31, E32, E34, E36

Below is the 17 pin connection color coded wires on the newer models with the BMW Connector 

X 18126

BMW CONNECTOR PIN# FUNCTION
FEMALE X18126
  YELLOW/RE 1 LF CHANNEL +
  BLUE/RED 2 RF CHANNEL +
  YELLOW/BLACK 3 LR CHANNEL +
  WHITE/BROWN 4 TELEPHONE MUTE
  VIOLET/WHITE 5 HOT in ACCY, RUN and START
  BLUE/BLACK 6 RR CHANNEL +
  YELLOW 7 I-BUS CHANNEL +
  YELLOW 7 EMPTY I-BUS
  BROWN/ORANGE 8 LF CHANNEL -
  RED/WHITE 9 HOT _at_ ALL TIMES
  BLACK/WHITE 10 VECH./SPEED SIG.
  BROWN/ORANGE 11 RF CHANNEL -
  BROWN/ORANGE 12 LR CHANNEL -
  GRAY/RED 13 ILLUMINATION
  BROWN/ORANGE 14 RR CHANNEL -
  BROWN 15 GROUND
  WHITE 16 ANTENNA CONTROL
  17 EMPTY





CM5908 Alpine w/ infrared slot, 89-93 e30


CM5804
Early e30 radio built by Alpine Electronics
AM/FM/Cassette, Dolby, no weather band or anti-theft
Bass and Treble sliders under volume knob on the left
Center cassette door over the display.
Mechanical FF and rewind buttons to left of door
One row of 5 preset buttons under the display
Function buttons, including Dolby button, on the right.
Yellow and white power pigtail w/ 2 pin Molex connector, antenna pigtail

CM5905 or CM5907
Common on e30 models, built by Alpine Electronics
CM5907 had weather band
Single knob (for volume), Sliders for treble and bass
Two rows of five buttons
Two speaker outputs, left and right, used with fader control on dash
Premium system had the fader feed the rear amplifier
Yellow and white power pigtail w/ 2 pin Molex connector, others plug in

CM5908 Alpine w/ infrared slot, 89-93 e30
Four speaker control, no fader control on dash
CD changer control with round socket in rear
TR1000, TR1600 and TR1008 (6, 6 and 12 disc changers)
BMW-specific data cable, NLA
BMW Alpine CD changer and a data cable. You can probably use either
the 88 88 1 600 178 (12 disc unit) or the newer 88 88 1 600 220 (6
disc unit) which superceded to the 82 11 1 467 002. Or basically any
*Alpine* BMW unit with a 13 pin plug arranged in 3 rows of 4 + 1 row
of 1. If the factory changer says CDX-M61 and has the same plug, it's
a Pioneer and won't work.

Pioneer (KE83ZBM) with the +/- (mode) in lower right corner
CD changer control
reported on 4/89 production 325i