Viermalvier.de, das Geländewagenportal Foren Marken talk Mercedes Fernlicht geht nicht -> Lenkstockhebel defekt

(Sorry about the English)

If this is a 1996->2000 463, then the problem is the very small contacts in the turn signal stalk. You can replace the stalk, but it will fail again. I added two relays for high & low into the relay panel under the glove compartment and solved the problem permanently. The lights are brighter and the old turn signal stalk provided enough current to switch the relays, so the whole project was cheaper.