I had this same problem when i tried to wire up the sub in my lupo, there are a few things to check; have you ground/earthed it? is the power cable got a good connection to the battery? is the blue remote cable wired correctly? I will admit its a bit of an arduous process but eventually the little green light will come on and it should work, if you have no luck with the checks just let me know and i will try and give you a solution