Mine doesn't have it either, but I tow with my pickup, not the Cayenne.

 

Asking for a friend who is a little slow….

This dummy thought you could just jam the new terminal into the unused side…

how does this purple thingy work? Is it some kind of lock mechanism? (So the terminal doesn’t really “click” into place, but the purple thing holds it in place?

sorry for the dummy questions! I’m no smarter than my idiot friend. 😇

 

The purple strip is a lock. It pulls out. Needs to be pulled out all the way before inserting the new terminal.
The terminal clicks in. Then slide the purple strip back in.

 

does anyone know how to retrofit into the back of the fuse panel for an OE look? Please share or PM thanks![/QUOTE]
Loosen the fuse block and slip an appropriate size female spade terminal connector into the spare slot. You made need to find an old terminal from a junk yard or get a pack of 100 off of Amazon for a few bucks. If you can find a powered spare fuse slot you can slide the female terminal straight into the slot from the back. If there is already something in that spot for something you don’t have, just slide it out with a depinning tool.