Check the condition of the wiper blades. If they are cracked or show any signs of deterioration, or if the glass swept area is smeared, renew them. For maximum clarity of vision, wiper blades should be renewed annually, as a matter of course.
To remove a wiper blade, pull the arm fully away from the glass until it locks. Swivel the blade through 90°, then depress the locking tab with a screwdriver or your fingers. Slide the wiper blade out of the hooked end of the arm, then feed the arm through the hole in the blade. When fitting the new blade, make sure that the blade locks securely into the arm, and that the blade is orientated correctly.