2003 GMC Sonoma Owner's Manual - Page 325

3. Remove the insert from the blade assembly. The insert has two notches at one end that are locked by 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. 5. Be sure that the notches are locked by the bottom claws. Make sure that all other claws are properly locked on both sides of the insert slots. A I I W 5-62