No problem mate, right my best bet would be to look for some where that the wire passes through or is tight against the bike or frame, then feel and look all round the wire to see what if anything has rubbed or pinched the thing. Again your making it difficult for yourself, don't think about where you think it might be ignore any sort of guess work just keep it simple, the wire is the most likely cause of the fault and until you have ruled that out stay simple. if your sure that's not the fault then start with your next best guess otherwise your going to be dancing all over the place and never get a handle on it. Do you have a multi meter? if you do then check the continuity of the wire from front to back, that will tell you if the wire is still good if nothing else. A wiring diagram will help you immensely with this sort of fault, dig around the net for one and use that to follow the route it takes around the bike.