What to do with YELLOW cable??

Installing a new ES127, discovered I needed to snake a 5m Spur cable thru a pedistal tube. Cut the cable and fished it out, only to find out that it was not long enough to get to a terminal block. West Marine gave me a Spur-to-Stripped End cable. No problem. Used (old stock) Raymarine junction box (white for old SeaTalk cable), but when mating both cables, the Spur cable has a YELLOW Cable, and the Spur-to Stripped End does not. What gives?? Is the Yellow cable connected to any of the other cables???
Thanks!