MSD Tach Signal GMR Pickup

One example is to connect the GMR, which stands for Giant Magneto Resistive, to a diesel injector current wire. This will produce a signal that can be used to trigger a tachometer or shift light! Another example is on late-model engine equipped with a coil-on-plug ignition system. One of the coil's primary current wires is simply routed into the pickup clip and GMR converts this pulsing into a 12 volt signal for a shift light!