Normally their is a blue wire, the blk/wht wire should be for a lite kit. if you have a lite this can be hooked up to the wire if you have two wall switches on the wall 1 for the fan 1 for the lite. if you only have 1 wall switch the blk/wht should tie in with the blk wires with the lite kit. if you do not have a lite on your fan just cap it off and leave it.