I replaced the battery about four months ago. Doesn't mean its not it but I had my friend (a mechanic) check the battery and its great. It may be the alternator failing as I bought the car used two years ago and I have no idea when the altenator was replaced (if ever) before I purchased it.

I was told by a BMW mechanic that the wiring harness in the "B" pillar which is right behind the rubber peice on the door is the issue. I checked this and found it to be corroded. Apparantly this is pretty common with my model as it gets water in it over time. I'm hoping this is an easy fix. I was thinking about stripping the wires and using fresh ends. Is there a part number for reference if I do need to replace the harness? I tried looking it up but there are so many options and I'm lost with it. I am pretty confident I can do this on my own so no worries there.

Thanks for the replies guys!

Andrew