Headlight wiper now in "digitus impudicus" position

It is held on by an 8mm(?) nut under the lift-up-and-slide-off hinge flap.

All the best, Peter.

You don't say what model/year, but on our '85 760 a couple years ago the splines stripped out (where Peter mentions). Replacement of the stripped parts was a hassle, so I cemented the pieces with blue Loctite and tapped the wiper on with a socket and a small hammer. So far, so good. Now I'm very careful to make sure the wipers aren't stuck down in the winter before using the wipers.

Mike

Yes, it's a 2002 S40.

Wiper arm seems to shift around between trips but gentle pressure doesn't move it, so stripped splines doesn't appear to be the problem.