1999 GMC Sonoma Owner's Manual - Page 279

yellowblue Windshield Wiper Blade Replacement Windshield wiper blades should be inspected at least twice a year for wear and cracking. See "Wiper Blade Check" in Section 7 in this manual under Part B "Owner Checks and Services" for more information. NOTICE: Use care when removing or installing a blade assembly. Accidental bumping can cause the arm to fall back and strike the windshield. 1. To remove the old wiper blades, lift the wiper arm until it locks into a vertical position. A. Blade Assembly B. Arm Assembly C. Locking Tab D. Blade Pivot E. Hook Slot F. Arm Hook 6-41