I have an old TAZ5 3D printer retrieved from storage. Years ago, I extended its cables poorly, and one is causing issues. I can’t identify where a lone black cable with a U-shaped connector originates or connects. I’ve tested all 14 pins, and none link to it. I’m unsure where it terminates inside the plug or where to attach it. The other cables I’ve identified include three grey ones and a black/white pair. This black cable has no paired wire.
Typically the black wires on Lulzbots are ground, and if they have a spade connector, they go on the grounding screw:
Agree but this “black” wire is outside the box and does not connect to any pin (of the 14) on the plug so it never enters the interior of the box. Is there a good diagram of each of the 14 pins and what they go to? That way maybe I can track it down. As for the U-connector I put that on so not sure what was there when I bought it when it first came out years ago. 
Perfect I think you solved it for me. THANKS…
I searched those articles too and guess just overlooked it. Thanks again..