digi dash. no revs, no speed. help

hi there, i'm having some problem, so i start to explain. hope i make some sence. lol

so, i have rally car, and i just fitted a c20xe engine, and a lcd digi dash.
i done the wirings as shown here in some threads, and i don't have a rev count, and speed count. everything else works.
i have to question. the wire that send the signal from the transducer, goes directly to the dash, or it as to go to the ecu first?
another, when i wired the green and black plug, i just use the green, and the blue wire. do i really have to use the brown\yellow or the brown\blue to make those things works? because the digi dash doesn't have a ecu ligh, so i don't need to connect it. i think.:wtf:
what is the best way to test teh tranduces and the rev sensor, to see if they are not broken.:confused:
if anyone can help. thanks:thumb:

the digi dash has a black and a white plug and the transducer wire goes direct to the dash blue/red iirc

thanks brainsnova. one less worry to head :D

and about the rev counter????