Checking Wiper Blades
WARNING: This page is about a different car, the 2010 Porsche Cayenne, 2009 Porsche Cayenne, and 2008 Porsche Cayenne. However, it is still accessible from the selected car via links, so may be relevant.
Check the wiper blades for any deformities and tears.
Turn on the ignition, activate the wipers and check the wiping quality.