I'm trying to rig up an electric speedometer from an Australian 1993 rev 2 3sge into a rev 1 JDM cluster, I've worked out the positive and negative terminals but attaching the speed sensor signal wire to either of the other two terminals does absolutely nothing to the needle no matter how much or little I spin the bloody thing. I know there is nothing wrong with the sensor itself as I've managed to get a good reading from it with an oscilloscope.
Here's an image of the circuit, if anyone could annotate exactly what each of the 4 terminals does so there is zero confusion that would be perfect

12v is bottom left,ground is bottom right.
purple wire goes to top left
purple/white goes to top right (not needed for testing)
 
you need to power the sensor and the gauge to test it,i made up a loom so i can test both sender and gauge at the same time