The two wires from the 700R4 VSS are connected directly to the 7730 ECM. Yel wire to B10 and ppl wire to B9. What does the ECM use these for? So far what I read, the yel (signal high) provides the 4K pulse and the ppl (signal low) is just ground.
I have a Dakota SGI-5C hooked up which requires the yel wire attached to the "SIG IN" terminal and the ppl wire spliced to ground. Then a wire attached from the SGI-5C "OUT4 (4K)" terminal to ECM's B10. No other instructions on what to attach to B9. Dakota Digital tells me the ppl wire is ground, but will not commit to telling me to run B9 to ground.
I'm cautious, well scared to fry the ECM if I ground B9. Any thoughts from the experienced members out there.
In summary.
1. ECM's use of B9 and B10?
2. Can B9 be left open or grounded?
3. What happens if B9 and B10 are left open?

Thank you in advance.

 

From the sgi you can Input a 4k magnetic pulse to b10 or optical to c6 with a programing change. B9 is a ground !

 

Thanks for the reply t/p.
So I just run a wire from B9 to ground?

 

B9 can be left unused if the sensor is grounded in the sgi-5.

 

The purple wire is not exactly a ground, it is a reference to be used by the ECM to compare the voltag produced by the VSS against. The ECM is what provides the ground in this case and does not attach to a chassis ground. I would attach the purple wire from the VSS to this connection as well as the VSS low input of the SGI-5.

 

That makes a ton of sense. Tying the purple wire to the SGI-5 is logical. As it is, the purple wire is attached to my VDO programmable speedo, which also has a wire running from SGI-5's "OUT1" to a terminal on the VDO speedo. I assume these are the high and low signals the speedo requires and works accurately. So based on my understanding, I will splice the purple wire and attach it to B9.
Thanks again Tuned Performance and Six_Shooter

 

Update - splicing the purple wire and attaching it to B9 worked perfect. I did not have to do any additional mods. I had to try the car with this mod for a while before I reported back. It's been 3 months of cruising and very happy with the outcome.
Again thanks for all the support.