1990 Mercedes-Benz 420SEL Q&A

1990 Mercedes-Benz 420SEL Question: stereo wiring diagram

My son bought a 1990 Merc-Benz 420-SEL -- he is trying to replace the factory radio with an up-to-date CD/radio system -- does anyone know where he can get a diagram of the wiring/speakers etc? Thanks. -
Answer 1
most libraries have an electronic reference called alldata. its gives wiring diagrams. -