4L80E Speedometer options?
got some diagrams and the general grounds the yellow wire internally in the pcm then looks for a modified ac signal to come back then interprets this as the vehicle speed. I then just spliced the signal wire for the speedo into the purple wire,left factory wiring alone and then calibrated the speedo as per autometers instructions and it is working like a charm almost a year later and no problems. The stock colors for the vss are purple, and yellow at the rear sensor. The front sensor is the input speed sensor. pm if you need more info.
later chris



