96 3500 4x4 no speedo

Have a 96 k3500 6.5 4x4. When got truck speedo didnt work. Looked under truck. Seen a plug/ sensor with nothing plugged into it closer to back of trans driver side. Moved some wires and found a 2 plugs that are the same plugged into of double ended female. Unplugged one end and plugged in trans sensor nothing. Then took other end and tried it speedo worked. Now no speedo. And check engine light code says no circuit speed senor. Need help. Wire colors were purple and green wrapped around each other.

One is probably the VSS signal, and the other may be for a secondary speed signal sensor on the transfer case. Some of the AWD transfer cases had THREE speed sensors, BTW. Search around the upper area of the transfer case for more connectors/sensors.

According to the diagrams, the wires should actually be purple/white and light green/black. There is a VSS connector on the transmission/transfer case assembly and a VSS adapter module specific to the 4WD models.