Today, three months after doing a 4 speed conversion from FMX I decided to change my speedometer cable. But when I took is off it had some sort of piece that connects to the cable on the part under the dash and has a black wire and a white wire coming from it? The speedometer cable for the toploader doesn't have it. What is this this thing? Does it affect anything? Can I just connect the new wire and forget about it? I looked in my service manual and I couldn't find anything about it.