hi mate i had all the same happen to my s2 about 4 month ago wire was ok bulb was ok id put a new starter and alternater on a few week befor so i didnt now wot to do but in the end it tured out to be the brush pack in the alternater was naffed and same as i say it was only a few week old so it could be any of them best thing to do is charge battery and start it up and the just drop a multey meter and the back of the alternater see if it ok down ther if its ok it might be the blue wire if not u might have a dry sell in ur battery sorry about the essay but hope this helps let me know how u get on jay