Period wiring harness used to install an additional pair of driving/fog lamps https://pbase.com/9146gt/image/25728903 ~ https://pbase.com/9146gt/image/28657189 and/or the BOSCH Fanfare Horns. This kit also came with a rare BOSCH on/off switch. What makes this BOSCH switch https://pbase.com/image/150439174 rare are the 'spade' type connectors and the smooth shiny black finish of the small plastic knob https://pbase.com/9146gt/image/136566769, notice how they are not textured or dull, like these https://pbase.com/9146gt/image/24004144. These BOSCH spade-type switches are getting much harder to come by these days and are highly sought after to those who know.

Links to sample photos of the very same BOSCH on/off switch used by the Porsche factory in the twin-ignition of the 914-6 GT https://pbase.com/9146gt/image/25692332 ~ https://pbase.com/9146gt/image/89596749 ~ https://pbase.com/9146gt/image/23962390

I found the harness kit for sale in eBay.De.