Parts such as the Horn & Winker Switch: Buttun, Horn, Screw Cross 5x20, Knob Switch, Spring, are included in the C110 General Export (140115) Horn & Winker Switch parts fiche.
The lowest price component in this Horn & Winker Switch parts-list fiche is the Screw Cross 5x20.
The eight C110 General Export (140115) Horn & Winker Switch component parts are all listed in this schematic.