Well, I'll be damned.......
The VW thingie is a vi brator!
Here's the can.
And here's what's inside. A simple bi-metalic strip that continuously makes and breaks contact with the wire going from the sender to the gauge. Now I have to figure out how (and how well) it works in my gas gauge circuit.
Ray! Get a 12 volt version of that other thing and check it out for us!