GMC 1998 Savana Van Owner's Manual page 280

Windshield Wiper
Blade Replacement
7. Turn the bulb to the left to remove it. Install the
8. Reverse the above steps to reinstall the lamp.
new bulb.
See "Normal Maintenance Replacement Parts" in the
Index for the proper type of replacement blade.
Replacement blades come in different types and are
removed in different ways. To remove the type with
a
release clip:
1. To remove the old wiper blades, lift the wiper arm
until it locks into a vertical position.