1. Check the condition of the wiper blades; if they have cracks or other signs of damage, or if they scratch the glass, replace them. Regardless of their condition, replace the wipers annually.
2. Move the windshield wiper arm away from the glass to the latch. Turn the blade 90°, press the lock on the base of the mounting block.
3. Move the brush from the lever. Do not forget to check the condition of the rear window brush (where it is installed).
Information copied from the website MercedesMAN.ru
