Joe:
The diagram is from the 'exploded diagrams' book that came with my E (but not with my C
). It sounds like your system is completely different - midway between my 87E and the 98 C! My C has the headunit in the dash, and the amp in the trunk, with 8 speakers. They have standardized so many other parts on MBs that I can't see why they don't do the radios with some standard format. It isn't as if the convoluted systems they install provide superior sound - just complexity!!!
__________________
John
2003 Firemist Red/grey leather SL 500
2015 Palladium Silver/black mbtex GLK 350
1987 Smoke Silver/burgundy mbtex 300E Sportline (SOLD)
Click to see 87 300E