Replace headlight switch
 

Can you tell me how to remove a defective headlight switch on 1992 300D or s?nd me to a reference.

Pull the knob off and there should be a nut that secures the switch to the dashboard. Disconnect the negative battery terminal. Remove the trim panels below headlight switch then loosen the nut for the switch and disconnect the wires. Connect the wires to the new switch, remount it in the dash, reinstall the trim panel and reconnect the negative battery terminal.