My 1994 E, 152K miles, was under wraps through the winter. Fired up fine in the spring and gave her a vigorous Italian tune up. Noticed that the turn signals stopped working, FROM TIME TO TIME, Likewise the wipers but not the fluid when you pressed in the stalk for Wiper/Washer.
Blown fuse? No. If it was a blown fuse nothing would work. This problem was intermittent.
Faulty stalk controls? Possible. Except as I checked through the system the Hazard Lights also malfunctioned at the same time.
Combination Relay: Likely problem. I removed it to get the part number ( about $126 at the Mercedes dealer). Reinstalled it, and voila, everything was working. sprayed leads with some wd 40 and so far the problems have disappeared. Seems to have been an issue with corrosion on the leads or connectors in the box.