1) Go to costco and buy a new battery 2) Check the here if the F-pump is getting pressure 3) Make shure you did not fry the Electricals = menning check the fuse box 4) If this does not work take to an electrical shop or a certified BMW TEC , not one of these hack of a FUCK back yard no-jack shit idiots act like they are tunners. 5) Check to see once the car is running that the altinator is chargeing onece the car is running 6)If you car has fog lights make shure that they work if not you might of have a grounding problem that is causing the battery drain.