In searching the forum, I have found two answers for the speed signal wire.
1. Is it the white wire in the white connector on the back of the A/C control box
2. Or the white wire on the middle gray connector with silver markings on the wire.
Note: there are actually three white wires on the middle gray connector, one has gray marks, one has a black line and one has a green line.
This is for the 2005 350Z.
Thanks