Engine/Transmission (1994 - 1998) 47RH / 47RE speed sensor

[wicked6]

Does anyone know what wires are for what on the 2WD 47RH transmission speed sensors. . ?? It's got 3 wires. . I've been digging (and e-digging) for hours now & cannot seem to stumble across the info. . Plus, I am too cheap to go out & buy a Chrysler manual with the schematics. . !



FWIW, I am planning on using the output of the speed sensor to drive an electronic speedometer for my repower project. . Thanks!

 

[vssman]

They are power, signal and ground. Power on these is 5V from the PCM. I don't remember the order but if I recall correctly, ground is in the middle. There are 2 pin styles - round pins on the early units and flat pins on the later ones. Other than that, they are the same. (Note: units made for DCX Europe use a 4 pole magnet instead of the standard 8 pole magnet used on North American vehicles). The other "difference" is that 4x4 use an adapter to the t-case and slightly larger diameter o-ring to compensate for the adapter's out of round condition (read transmission leak problem). The unit is made up of a hall switch sitting near the 8 pole rotating magnet. As the switch sees a pulse it switches output from "high" to "low". They used to be made in the US and are now in Mexico... but that's a long story.

 

[wicked6]

They are power, signal and ground. Power on these is 5V from the PCM. I don't remember the order but if I recall correctly, ground is in the middle. There are 2 pin styles - round pins on the early units and flat pins on the later ones. Other than that, they are the same. (Note: units made for DCX Europe use a 4 pole magnet instead of the standard 8 pole magnet used on North American vehicles). The other "difference" is that 4x4 use an adapter to the t-case and slightly larger diameter o-ring to compensate for the adapter's out of round condition (read transmission leak problem). The unit is made up of a hall switch sitting near the 8 pole rotating magnet. As the switch sees a pulse it switches output from "high" to "low". They used to be made in the US and are now in Mexico... but that's a long story.

Hmm. . welp - PCM is MIA. . LOL! WTF - Enough acronyms. . This has the round pins, not sure on the pole count. . I guess I can wire in a 9v battery & count the # pulses/rev on an analog meter. . ?? Do you think it'll be OK with 12 VDC powering the signal, or should I use a resistor to knock it down. . ?? Middle is ground. . I think I got it. . The TCC / OD connector uses the middle for power... I guess I can meter my Dad's 3500 for the 5 V lead & go from there...



Do you know if the VDO electronic speedo will have any problems interfacing with the 8 pole sensor signal. . ???



Thanks -



Linc

 

[vssman]

Yours is an 8 pole magnet. Not sure if it'll work with the VDO speedo; but the same company makes the VSS unit. I'll try to dig up my shop manual for the tracer colors. Although you probably would be OK with 9V, I'd knock it down if possible to 5V. The hall cell is from Allego micro - 3142 if I remember (it's been a long time). There's also 2 4700pf caps across each leg with the center being common.

 

[wicked6]

Yours is an 8 pole magnet. Not sure if it'll work with the VDO speedo; but the same company makes the VSS unit. I'll try to dig up my shop manual for the tracer colors. Although you probably would be OK with 9V, I'd knock it down if possible to 5V. The hall cell is from Allego micro - 3142 if I remember (it's been a long time). There's also 2 4700pf caps across each leg with the center being common.

sweet. . This is great info. . Worst case scenario, I *have to* use a 727 mechanical drive & install the VDO VSS. . Being cheap (and pretty easy, if you ask my wife) that's a tough expense...



ECM Pin B27 is the Wht/Or lead (I assume signal from the HE switch), ECM pin B31 is the orange lead, I assume PCM 5v+, and the last is definitely ground (blk/lt blu). . I did pick up an ignition ballast resistor which'll keep the supply volts down, if VDO thinks the VSS will work...



Thanks VSSman...



Say - what's VSS stand for in your title. ???



:-laf

 

[vssman]

Per the 1996 service manual. Referencing page 8W-30-14 it has the following:

5 volt supply = 18 gauge wire orange color no tracer runs to pcm B31

sensor ground = 18 gauge wire black color / light blue tracer runs to pcm A4

signal = 18 gauge wire white color / orange tracer runs to pcm B27

Note that they are listed as 1, 2, & 3 in the order above.



Yup... That thing was my baby many years ago...