gkm24 wrote:

I have wired my VSS, which is a Ford E9TZ-9E731-A, into the ECU of my EFI install. Doe it matter which polarity it is wired into the ecu as it probably just sends a signal. 
Secondly, I am installing an auto meter speedo which uses the same signal but it says to use the high signal from the VSS but only shows as using the high side and not the other terminal. Does it just need the high side signal and earth to make it work?

I take it that the "High side" is a positive.

Any help very welcome. Thank you.

Unfortunately it's not like a straight DC 12v and ground. That is a 2 wire VR sensor which creates a pulse as teeth go by it. Your EFI should have instructions on how to pick up a VSS signal and will probably want to use both the + and - side. For the gauge you can try the + side and then if the gauge has a ground use that same ground for the - side. These kinds of sensors can be a bit tricky as you can measure measure them with a DC voltmeter, but you'll need to spin the wheel or gear or whatever to generate a signal.

Hope that makes sense.
 

Last edited by Raymond_B (5/02/2023 2:36 PM)