Being built late 86 your car is a MY 87, as shown by the green wire that indeed appears starting this year. So you should be following wiring diagrams for 87, not 86. Do you have them? If not drop me your email by PM and I can send you a zip file with all factory diagram JPG files for this year. They are zoomable and easy to follow. They are in English except for wires colors which are labeled in German, so you need to look for GE (meaning yellow in German).
The connector you are showing appears on the diagram with four branches like yours.
You need to look for a welding point, as shown on this pic where I'm showing all branches for circuit 50. This is for MY 87. Circuit R from ignition switch is a green wire as you can see.
