Ford Mercury Villager 1997 Owner's Manual page 302

To replace the wiper blades:
1. Pull the wiper arm away from the windshield and into the
lock position.
2. Turn the blade at an angle from the wiper arm. Push the lock
pin to release the blade and pull the wiper blade down
toward the windshield to remove it from the arm.
3. Attach a new wiper blade to the wiper arm and press it into
place until you hear it click.
Replacing the wiper blades
298