Looks like you need one of these:

http://catalog.peachparts.com/ShopByVehicle.epc?q=&yearid=1984%40%401984&makeid=63%40%40MERCEDES+BENZ%40%40X&modelid=6192%3AED%7C10000135%3AMBC%7C1504%40%40300D&keyword=brake&subcatid=W0133-1615804@@Brake%20Pad%20Sensor%20Cable%20-%20Front%20Left&mode=PA

Or you could just repair the wire.