I have a tach that I bought 13 years ago that mounts on the column. The only identification on it says 'Engineered in Japan'. There are 5 wires coming out of it.... 2 red, 1 black, 1 yellow, and 1 blue. One of the reds goes to the light, the other to the housing so I've figured that they go respectively to ignition and ground. Anyone know where the black, yellow, and blue ones would go?