I am putting a classic instruments guage into my 57 Chev truck. Installed a 01 4.8 w a 4L60E and a FITech ultimate LS w/trans controller.
I am no wiring genius and am stumped on one issue.
The electronic speedo has to be connected to the VSS The gauge instruction says:
( b. One (either) wire of an electronic transmission 2-wire vehicle speed sensor [VSS]. i. Connect the other wire of the VSS to the same point as the wire harness Black ground wire.)
Do I disconnect the wire from the FITech wiring harness or do I just tap into these wires. (two wire )

 

I've just tapped into the VSS for the speedo signal and it doesn't seem to effect the other circuits.

 

Does it matter which wire you tapped into.

 

Can't remember wire color but it's the one that sends the pulses to the ECU. If one is black, that should be ground.