I have some very basic understanding of electronics, like what goes on inside transistors, diodes, CDI, or inside the engine ECM. But only very basic stuff that I learned back at MSOE in the early 90's. Perhaps other brighter minds here can teach us details on how some systems on our bikes work? For instance, I am trying to install an electronic gauge set from a Vulcan VN1700 into a fairing I am installing on my Vulcan VN1600. I'm working with another home wrench doing likewise on his VN1600 Nomad. He has the gauge set mounted and has most features working, but has yet to get the speedo and tach working. The VN1700 gauge set is very shallow, all the inputs are electronic, and do the automotive style "sweep" when fired up. The ECMs for both bikes are similar, but not enough. For example, both the VN1700 and VN1600 have a speed sensor at the tranny output shaft sending a signal to the ECM and on to the gauges. But each puts out a different signal because of the sensor coil and number of teeth on the output shaft. So, am I right to assume all these gauges function on some sort of a voltage signal? The sensor produces a signal to the gauges, water temp, oil pressure, voltmeter, even the speedo, as a voltage signal that is calibrated to show what we need on the gauges. I'm assuming the ECM modifies or refines the signal to a smooth trimmed voltage signal to the gauges so we don't see flutter or twitch on the needle. So on the VN1700 gauges, getting a signal from the speed sensor on the 1600, the signal should cause the speedo to react, but perhaps not at the right calibration relative to the bike road speed?