What are car stereo wiring color codes for a 1986 528E BMW?

The car stereo wiring color codes for a 1986 BMW 528e are easy to follow. The radio switched 12V+ wire is purple, the ground wire is brown. For the front speakers, the left front speaker wire (+) is yellow/red, the left front speaker wire (-) is yellow/brown, the right front speaker wire (+) is blue/red, and the right front speaker wire (-) is blue/brown. For the rear speakers, the left rear speaker wire (+) is yellow/blue, the left rear speaker wire (-) is yellow/gray, the right rear speaker wire (+) is blue/purple, and the right rear speaker wire (-) is blue/gray.