Okay guys, I need some help wiring in a shift light. It has three wires, power, earth and Tacho signal. The power and earth are in and working fine but can't get a signal through the last wire. They all lead into a small circuit that has a microswitch. When you get to the limit you want the light to activate, you press the switch and it stores the signal value for the Tacho from the ECU, thus everytime that value is reached the light comes on. The problem is I'm not getting the signal from the ECU. I have it all wired up and am using ECU terminal 2 as per the service manual but no luck. Could I be using the input side of the ECU and not the output side? How do I tell the difference? Is there a difference in signal from input to output such as frequency converted to voltage? Sorry for the long post but I'm stumped.