On my 94 accord ex....I removed the speedometer from the gauge cluster and found a circuit board that plugs into the back of the speedometer motor....I'm going to say that is the speedometer head. I've fixed my problem, by the way! I swapped my speedometer assembly out with another one and it works fine. It would also jump to 20mph when the key was turned on, but it would accelerate from there when I would go. So, I turned the key on, and removed the needle...then I placed it back on at the 0mph mark....now it works perfectly.