I am trying to find where to splice into the tach signal wire. I have been told it is a little coupling in behind the passanger side headlight... there is no coupling or anything like it there. Only the battery and then the air intake and then the fuse box. Does anyone know where the signal wire is?

Please use your old threads rather then make new ones.
I'm not really sure how much more specific I can get I have given you all the info you need.

There's a small black rubber piece located near the battery and behind the headlight which will have a blue wire connected to or coming out of it. That's the wire you want to splice into. Here's a picture if it helps at all.

http://www.autotoys.com/installphotos/civicalarm01/civic01alarm9.jpg