If it is the CD changer plug then it would be:

Pin 1 = brown (ground, chassis)
Pin 2 = red with green stripe (permanent battery power)
Pin 3 = white with red stripe and yellow dots (kbus, databus for controlling changer)

If it is the Aux-In plug it would be:
Pin 1 = black (right channel)
Pin 2 = yellow (left channel)
Pin 3 = brown (ground)

I think you are looking at the CD changer plug.