Pipsisewa

I just installed my Greddy Turbo Timer in my FD this weekend, but I ran into a road block (figuratively).

I used the wire harnes that Greddy makes for this install, but I still had to splice into the speed wire, which I didn't do. I spliced into the E-brake wire just fine, but had no idea which wire was to the speedometer. I don't have an owners manual so I can't look up which wire this is. Can someone please help me out so that I can fully utilize my TTer.

thanks