Buick 2004 Rainier Owner's Manual page 345

3. Remove the insert from the blade assembly.
The insert has two notches at one end that are
locked by the bottom claws of the blade assembly.
At the notched end, pull the insert from the
blade assembly.
4. To install the new wiper insert, slide the insert (D),
notched end last, into the end with two blade
claws (A). Slide the insert all the way through the
blade claws at the opposite end (B). The plastic
caps (C) will be forced off as the insert is fully
inserted.
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