You did not state what year your car is, I have a CD manual and looked at the schematic for a 1987 560sel, didnt look at the others, anyway if Im reading this correctly the pins are as follows:

1. WT/BU
2. WT/GY
3. WT/YL
4. WT/GN
5. WT/RD
6. WT/VI
7. None
8. WT/BK
9. YL/GN
10. BR/GN
11. None
12. None
13. BK/R

hope this helps