Replaces the original petcocks and moves them to the other side of the gauge. I'm missing the original lamp fixture to go with this but I have a era correct dash lamp to replace it with.
Dang, these old gadgets are so cool!
I would presume there is a float in that larger round chamber that completes the circuit to ground much like a 1915 horn button but instead of honking the horn it lights a light when there not enough oil in the chamber. Not a bad idea but I wonder where/how they mounted the light since they say there are no holes to drill and no changes get made.
John,Yes there is a float. The light might have been similar to this dash board clamp on lamp used on the Ever Ready automatic oiler.
Here's a link to the Ever Ready Oiler from a past post