Agree with cleaning it first, but if that doesn't work....

First option is to take it to the dealer if it is brand new. Let him worry about it. They should do it in 2 minutes while you wait, if your dealer is paying attention to the value of your time.

If you want to do it yourself, proceed as follows:

Think of the rubber wiper blade, in cross section, as either having a leading or trailing edge where it touches the glass. If it has a leading edge, it shudders. The blade edge 'flops' backward and forward as the arm reverses direction, so you have to be a ways out before it will shudder. First, check that the blade is seated properly, and everything looks right (it isn't falling out). Then, if you need to align it, apply a twist to the wiper arm in whichever direction is required, to fix it. Back when wiper arms had flat profiles, it took an adjustable crescent wrench and 1 minute. With the bulkier BMW arm, you need to find a way to apply the twist without damaging anything.

Jeff

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2007 X3 3.0si, 6 MT, Premium, White

Retired:
2008 535i, 6 MT, M Sport, Premium, Space Grey
2003 X5 3.0 Steptronic, Premium, Titanium Silver
2002 325xi 5 MT, Steel Grey
2004 Z4 3.0 Premium, Sport, SMG, Maldives Blue