I'm installing a navigation system in my car. It says to hook up a wire to the speed sensor. I looked behind my glovebox and there is a group of three exposed wires, one gold, one green and one black....all ascending in width. Which one is the speed sensor?

 

isn't the speed sensor generally connected to the tranny??? (I'm not 100% sure about civics, but thats where it was in my old car)