Mercedes S500: How to Repair Wipers

1. Locate the windshield arm spring lever near the wiper motor nut. Pull the wiper to its servicing position. Locate the connector for the rain sensor inside the wiper arm near the spring lever and disconnect. Ensure the wiper nut it securely connected to the motor bolt using a 1/2-inch ratchet wrench and the appropriate sized socket.
2. Use the 1/2-inch ratchet wrench and socket to loosen and remove the wiper nut. Carefully pull the wiper arm off of the motor bolt and pull the rain sensor wiring out of the inside of the wiper arm. Inspect the arm for bends or cracks and check the rain sensor for damage. Replace the wiper arm if necessary. Run the wiring through the inside of the new wiper arm until it reaches the spring lever. Slide the wiper arm over the motor bolt and secure the nut using the ratchet wrench.
3. Use a slot-head screwdriver to pry off the wiper blade connector. Remove the piece after being unclipped and slide the blade assembly out of the U connector. Insert the new blade assembly into the U connector and snap the clip on top of the metal joint (this requires some force).
4. Check the wiper fluid reservoir. Look for cracks or pinholes in the fluid line leading to the wiper motor from the reservoir. Replace these lines if necessary. Put in antifreeze washer fluid in the lines to keep them from bursting during the cold seasons.