Wiring diagram for E2, european model.

Hi all! Thanks for letting me in here! 
I discovered a blue/brown wire inside the main light bucket today. It has a female round connector at the end. What is it for?
Does anybody have a wiring diagram, or a similar bike to tell me?

Z1000ST E2 1980, Windjammer fairing, saddlebags and top box.

Sounds like the brake light connector.  There should be a jumper that connects the front master cylinder switch to that connector.  This guess is based off reviewing some other KZ manuals.  Kawasaki standardized the wiring colors across various bikes.