I have a 2003 FXST, I would like to install a HD headlight modulator (part # 91706-82) on, I have the unit but no wiring diagram, it is new, never installed. The local HD shop doesn't have a diagram, neither does the factory shop manual I have. Anyone have an idea which wire hooks where? It has a black wire, gound?, A red wire , and a white wire. Thanks!!!