My best guess is you are looking for a tan/Y wire, coming from the dash, that is for the tach. This is the color of the wire from your engine bay/ECU that you have likely cut off. I do not have an EVTM for your year, but I referred to diagrams at Autozone.com. (It's also T/Y in 1997, which I DO have an EVTM for ...)
I'm not sure what style connectors a '94 has, as all '95 and later Rangers have a big square 42 connector from engine bay to inside the cab.
So , just look in whatever connectors your year has.
Your tach will likely need to be recalibrated, as well. According to my info (I'm sure there's info on this site, I was viewing RPS) there are (2?) set screws on the back of your tach module to claibrate it. This will require hooking up a known tach to verify your reading, but it apparently works well.
Hope that helps.