I see this thread is pretty old..
I am not saying the hoses are bad too but look at your hoses,, and while you are in the area of taking things apart, clean out all the old debris, leaves, etc... the gasket that seals the pumps with the tank .. etc.. the plastic fender rivets are about $6.00 at the stealer.. for less than $10.00 at hearbor freight you can buy hundereds of rivets in a box.
Best you get the oem pump,, the cheap Autozone pumps work great, and last a long time, but use quick connectors.. I prefer the original connectors. So, check with the guy who says he has some in this thread. Or see if you can get the pump with the proper connector from all the online sources. EBay probably a good source or Amazon. Or anyof the BMW online sources.
If the pump is not working, I would also check the fuses, in the glove box, and in the trunk are many fuses,, at this moment I can't remember the exact ones you need to check. in this forum, I think there are fuse diagrams.
test the new pump with straight water, once you decide it is ready, not leaking, everything clean,, hoses are good.. and ready to put the reast of the parts all back together, then fill with the proper fluid. test again,, and put the plastic fender skirt back and the rivets. (btw, it's very easy to tear the hoels in the plastic fender skit. Be careful as it has to pulled tight to align the holes.