here's the Question. On early model thirdgens w/ an optical sensor VSS, did the actual sensor need power? i'm not asking if the small buffer box (little yellow thing) needed power, as i know it would to convert a signal, however would the regular sensor? The questions comes from a thought on why would there be three wires, red/green/black coming from the yellow box, and all going into the sensor, as if there was no power needed at the sensor then u'd only have two....maybe one.

Also, on the later model thirdgens w/ a VSS in tranny...what wire carried the signal...should be a yellow and a purple wire, are they interchangable as to which gives signal, and which is grounded? That's the only explanation on those i could find from the search engine. Thanks in advance.

 

On the 'birds with the buffer box, the yellow and purple wires run directly from the box to the sensor on the trans.
I couldn't find any info on the optical sensor, but would assume that red is positive, black is ground, and green sends the signal to the ECM.