What pulse per mile signal is the 727 ECM expecting from the VSS? I'm using the stock speed sensor from a 1993 GMC Typhoon transfer case. I'm not sure what signal it is sending and not sure what signal the 727 is expecting. I do know that my speedometer multiplies like crazy. For example, 1 mph turns out to be around 11mph, and it multiplies from there.

There is a flag (in the $8d code at least) to switch between magnetic and optical.

No idea what the S10 outputs.

I've worked with the VSS both ways. Anyway, I have noticed that I have different results with the 1227727 than I do with the 1227730. I'm currently rebuilding the wiring in my S-10 and will know very soon if I'm still having problems. I'm willing to bet I still have problems.

The Syclones, use a DRAC.
Pin C13 of the DRAC to pin C6 of the ecm.

B9, and B10 on the 730 go to the magnetic sensor.


If your S10 has the optical VSS in the back of the speedo you can just use that.

The 727, 730, and 749 are all built on very similiar Printed Circuit Boards. So it's a just a matter of lining up one pieces from any one combination, and then setting the code for the right option for the VSS, and the PPM scaler.

Thanks. I'm going to have to order the correct DRAC from United Radio. For anyone who does not know, GM buys the DRAC modules from United Radio and marks them up about 100%. I called a few years ago and they were willing to make one for my application for something like $50.00. All they need to know is the tire size and gear ratio. There is no core deposit from what I can remember. United Radio is located in Syracuse, NY.