RB25DET VSS Wiring

[OutToWinPAHC]

Finding good diagrams of the lower harness are hard. Anyhow I was wondering if anyone knew which wire on the VSS was signal, and which wire was ground. These are two wire VRS VSS so by design one wire is ground and the other should go to the cluster via a series of connectors. Wires are Yellow/Blue or a green I think, and a light gray or white with a red stripe.

[TimTurboZ]

You don't need it...speedo signal is separate. In s14's it is for sure. Figure s13 still would not need to go thru the ecu. The interior plug is from a chassis harness on the s13 but the speedo wire goes to the transmission sensor I'm fairly sure, I had the wire get rubbed thru on my old coupe

[OutToWinPAHC]

I have no idea what your saying. but it goes like this VSS to the cluster, cluster to the ECU, ECU to the hicas ECU. However through the series of connectors I appears to loose color, so I wish to see who may know which is which.

[Carl H]

doesnt matter, vss is an ac pulse generator.
connect to chassis pins and roll w it.

[Darius]

He is asking what color the chassis wire is that he needs to connect the VSS wire into. I can't look it up right now, but it is surely in the S14 FSM.

[Carl H]

on the skyline the vss signal from the speedo to the ecu is yellow/green.
on the s14 its a couple of red wires with various tracers.

iirc the speed sensor is a yellow/blue and grey/red on the 25 harness, speedo generates the pulse the ecu sees.

[OutToWinPAHC]

Actually it goes from vss to the speedo. The speedo is 4 wires power, ground signal in, and the converted signal out, the ECU has a comparator circuit which uses engine load and speed and reports back to the Hicas ECU where that unit controls the electric steering rack based on the values it sees including the front steering pressure and angle sensor.

The issue is that I do not have continuity from the VSS to the speedo. Which happens to pass through about 4 body connectors which all visually look good (some require removing the dash to check). Wheel well harness much like 240sx looks good too. So my plan is to rewire VSS to the cluster, and cluster to the ECU. But since I have noting to compare to I was looking to see who knew which was was which at the VSS factory, then I have to determine which of the two terminals is in and out on the Speedo.