The wipers on my 2000 X5 4.4i seem to have a mind of their own. They come on by themselves and won't turn off no matter what I do with the stalk. They don't do it all the time and sometimes when I turn off the ignition and re-start they behave themselves properly. Yesterday I used the wipers on the rain sensing setting and they worked fine until it stopped raining and they just kept going.

Any help would be appreciated. Can I get at the contacts in the base of the stalk, perhaps clean them? How do I do this?