WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
Bend wire end approx. 10 mm and insert in notched tip.
Pierce wire starter with uniform pressure through adhesive bead, wire end (bent part) must be positioned on window glass.