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

i have a 2003 Z i hooked mine to the white wire on the middle gray connector worked fine for me. Im not sure about the silver markings on mine there was a pink dot every inch or so.

you should use a DMM to test and verify which wire is the VSS.