This is just a suggestion , but i would go to a bike shop and have a look at a bike just like yours to see if you see which coloured wires go where ! even draw on paper as best you can and try to match them up , sometimes you may find by asking them at the counter they may tell you what you need to know , i'm sorry i don't have a bike but i thought you may appreciate the suggestion , even type the make an model of you bike online and refer to the word electrical scematic after the name of your bike and model or manuals and see what comes up ?
hope this helps ..