I'd guess that you have a bad wire for the wiper park signal... should be red black... be aware there is another one in the same left harness which is red blue or red black for the hatch release.
I'm having all kinds of fun tonight playing around with mine... see my thread.
Also www.bmwe34.net has a great pdf with the color codes for each set of harnesses.
You may wind up fixing more than that once you get in there.