Installing Tach in escort

once again here i am. My 1997 ford escort LX is getting a tach. i have pos wire ground wire dimmer light wire then the wire that reads RPM the pos and the ground works because the needle moves when connected and the instructions say the RPM wire is light green with red stripe and i found that wire and spliced it but no RPMS the dimmer light wire does not need to be spliced to does it? because i get power without it. Or am i just splicing the wrong wire PLEASE HELP I want to try and have this done for the weekend.
Thanks guys
~OTTO~

Yes the LG/R comes from the PCM and goes to the tach. My schematic also shows a 10 amp meter fuse on BK/Y going to the tach for power and a BK/GN wire going to ground. On the coil there is a BL/LG wire and a R/LB wire coming off of the coil. One of these might count RPM's for your tach. I've read at least 2 threads about the tach not working. Don't know if those involved ever got it to work.

Ok thanks dave in anyone else has an input ill still hear it i will have to try the wire on the coil.