there is a wiring difference between <86 and 86+ 107 CCU's, and this was probably a corp-wide change. I don't know if they are plug interchangeable, but they are definitely not electrically interchangeable, and the 86 is not "backward compatible".

__________________
86 560SL
With homebrew first gear start!
85 380SL
Daily Driver Project

http://juliepalooza.8m.com/sl/mercedes.htm