Motorcycle Repair: headlamp install on 2000 fxstd, duece, buld

Question
bought after market headlamp for my duece.
It came with only two wires leading from the lamp.
my duece has three wires leading from the existing lamp.
what to do?
thanks

Answer
Check the buld and make sure its a two filiments. If it does you need to figure out which one is the high and which one is the low. SInce you have only two wires then the housing of the light must be the ground. Ground the housing and touching each wire to a hot lead you can tell which one is which
Good luck and happy riding
Mike