I'll start off by saying I've found a number of threads where folks mention it's "relatively easy" to swap from mechanical pre-92 speedo to electronic 92+ using the Marlin Crawler VSS conversion module and 92+ electronic gauge cluster, however no one mentions or seems to know to actually wire the VSS into the system. I asked Marlin Crawler, they didn't know. I tried calling both ORS and ToyOnlySwaps and they both said they thought it might work, but weren't really sure, so I'm hoping someone on here has done it or has more knowledge of that speed sensor circuit and can provide some info.

From what I can understand, the 3 pin marlin crawler VSS just needs power and ground to those respective pins, and then I think the signal wire would be run to the appropriate pin in the cluster connector (everything I can tell about the system seems to go speed sensor > cluster > ECU). I can't seem to find out if this is correct, though, or if anything would need to be done with the ECU, etc. Ideally, I'd like to get a 92+ cluster, hook up the Marlin VSS adapter to the transfer case, run IGN power to the power pin on the adapter, run ground to the SPD ground pin on the cluster, and run the signal wire to the SPD signal pin on the cluster. I'd like to know if someone has actually done this though and if this would work.

I'm only doing this because I'm tired of the noisy mechanical speedo in my 1991 3VZ M/T 4x4. I've replaced the speedo cable with a brand new OEM unit (not cheap) and while I was next going to look at replacing the speedometer unit itself, I figured why pour more into the system if I could swap to VSS with an electronic cluster and be done with it. The question is, would it work. Eventually down the line I plan on a 5VZ swap so I'd like to not overly piggyback things if it will be too complicated so I can make the swap as smooth as possible, if that makes any sense.

 

this not much help but when I swapped a '92 22RE into my '91 Toyota the harness had a plug for the electronic speedometer. That would be a option, finding a '92 front harness but take some hours to swap.
Disconnect speedo cable during the cold months for a quieter ride.

 

Are you saying your existing dash harness had a plug into which the VSS could be connected, or that the cluster connector had a pin for the speed sensor?

Somewhat related, technically all the trucks, even those with mechanical speedos, had an electronic speedo output to the ecu. On mechanically driven speedo vehicles, the mechanical speedo outputs an electronic pulse signal back to the ECU (and CC ECU if equipped) so the computer knows the vehicle speed.

 

This post was moderately helpful.

https://www.toyotanation.com/threads...sensor.117684/
I'm not sure what this person meant by "on the same side the ECU wire enters the speed meter", if that's to say the same pin location or what. If it is the same pin location, it seems it would be easy to get a 92+ gauge cluster and the MCI VSS, and wire the signal wire to the same pin on the 91 cluster harness that currently runs to the ECU, but I'm not sure if that's correct.

 

the ‘92 harness which i used during the install had plug for electronic speed sensor…i wondered what it was and then looked at my spare transmission and saw it was electronic speedo

 

Got it, that makes sense.

Toyota switched to an electronic VSS at the transfer case from 1992+. Before then was cable. I’m trying to determine how that VSS is wired into the cluster and/or ECU.