Just an FYI, I just installed my D3 in a 2006 Nissan Frontier. The dealer gave me a print out from 12volt which showed the VSS as a light blue wire in the radio harness. There IS a light blue wire in the radio harness, so I properly connected to that.
During shakedown, I found that the VSS was not recognized. SO I did a little more searching here and found another 2006 Frontier owner. He sent me a link which showed the VSS being installed in an empty hole of the cluster plug.
I put the wire in this hole, did some testing and it works.
My point is, the information given for the 2006 Frontier by most sites is inaccurate. You will need to attach the VSS to the cluster plug.