Sorry, but I don´t have a wiring schematic handy (used to have one in my cell phone case for long distance trips), but I´m just about positive a wire goes to the ignition coil located in front of the oil tank. If you purchase the HD repair manual, there are schematics for both the early and late model 1985 FXEF. The difference is the type of starter solenoid that is used on the bike (mine´s the old one), but early or late doesn´t affect where and how the tach is hooked up. If you do one job on your bike, the factory manual will pay for itself compared to what the HD Stealerships charge on an hourly basis.