speedometer wiring question

I posted this question before and didn't get a reply so i thoght I would ask a different way. My new 231 transfer case has a three wire speed sensor plug but my 92 cherokee has a 2 wire plug on the factory wire harness. I know that in 92 speedometer cables were done away with and the speed sensor was introduced. My question is what year did they stop using a two wire hook up and go with the three wire. Does anyone know what the two wires going to the transfer case speed sensor are for, (voltage, sensor, ground, etc.) Any little bit of info will help as I have to try and splice these to plugs together somehow. Thanks

This is from the 98 service manual but should help

Three wires, purple/orange is power
brown/yellow is sensor return (ground)
white/orange is speed sensor (to speedo)

Do you have the 92 sensor and gear? That should swap right in.

Just read your post regarding the speedo sensor on your '92 Cherokee. I'm dealing with a similar situation in that the t-case I'm trying to install has the JB Conversions super-short SYE installed and only has the option of the 3 wire sender. Were you able to figure out a way to splice the stock '92 2 wire setup to the later style 3 wire setup? Thanks: Chris

QUOTE:
I posted this question before and didn't get a reply so i thoght I would ask a different way. My new 231 transfer case has a three wire speed sensor plug but my 92 cherokee has a 2 wire plug on the factory wire harness. I know that in 92 speedometer cables were done away with and the speed sensor was introduced. My question is what year did they stop using a two wire hook up and go with the three wire. Does anyone know what the two wires going to the transfer case speed sensor are for, (voltage, sensor, ground, etc.) Any little bit of info will help as I have to try and splice these to plugs together somehow. Thanks

I just got done looking at the 95 and 93 fsms and the 3-pin arrangement from r-->l is pin 1: vehicle speed sensor output(white/orange), pin two: ground(black/ light blue stripe(93 fsm), pin 3: voltage input(orange 8v--95fsm). If you don't have the 3-pin connector already, I would cut one off at the JY. You should measure your two wires with the ignition on and have the ground probe to chassis ground. If it's two wires, I guess one would be voltage input and one the output. You'll be able to figure the Vin easily enough, but the second wire I would double check to make sure it isn't a ground by doing an ohm test b/t that and the chassis ground. If it is the Vout, then I would run a short chassis ground to pin 2 of the connector on the Vss.

Did this work, and does anyone know what the wires are on the two plu version of the t case, the older 242. Thanks