greddy tt reading km/h

[sliEighty]

I am one of many 240sx owners that their speedometers dont work. I dont have a problem with the fact that i dont have one, but it wont pass inspection that way. On the greddy tt it has an option to read in km/h when you wire the purple wire to the speed sensor wire yellow/green, but with the speedo not working and still having a speed cut I am confused on where to hook up the purple wire and if i have to have the JDM VSS

[GSXRJJordan]

If you've got the JDM speed sensor, and your chassis wiring in intact, then you'd tap the same wire that goes from the dash harness to the speedo. I don't remember the color off-hand, but it's in all the SR20 swap wiring guides.

[sliEighty]

yeah i just dont understand why if everything is intact and i have the usdm speed sensor in why my speedo doesnt work, thats what i mean, if that isnt working should i still splice into the yellow/green?