here's what i'm referring to, just give it a check...
remove the 2 bolts (encircled yellow) to remove the front sprocket cover
see that thing just below the sprocket with a small screw on the head with a green wire (with red stripe) check if the small connector is disconnected or broken, if its broken you can solder it back
you can verify this by checking the wiring diagram posted earlier, its a light green with red stripe connected to the 'gear switch' leading to the neutral light indicator.....hth