From the factory, the tachometer is wired in series with the system, basically requiring the tach to function for the engine to run. This bypass method uses a two wire trailer hitch connector available at most electronic and auto parts stores. Connector 1 is wired essentially like a jumper connection to allow power flow to the ignition coil independently from the tach. Connector 2 is wired to allow the tach to function and to receive power from a separate ignition source. Now if the tachometer should fail, the engine will continue to run.