late model c101 pin 14...

[bimmer630]

Im about to connect black/white pin 14 to the VSS on the back of the E30 cluster.. but where does this wire go after the E30 body side of the C101?

I want to find the other end of it and connect to the cluster.. but what was that wire used for originally? the old ETM doesnt really give a good explanation of c101 and where each pin goes

[bimmer630]

...Or am I over complicating this? I read on RMeuropean auto parts swap page that speed signal wire pin 14 has to be connected directly to the plug on the back of the cluster.. but right before he writes that, he mentions a 325e.
maybe i dont need to worry about the cluster if im swapping into a late model (1990)?