[Dave at Pelican Parts]

I don't believe foglights were a dealer add-on item. I believe they were factory. By 73 at least, it seems that VW/Porsche/Karmann had found it was easier to just have a single wiring harness for all cars, no matter the options.

So you should find the relay socket for the foglight relay, and you should find the wires in place--roughly. The ones under the dash may be folded up and tucked out of the way somewhere, or folded back along the main harness or some such. The ones to the lights should still be there, either in the trunk or out in front of the front panel but behind the bumper.

--DD