Brake sentinel?

[Veriwide]

I'm running down the wiring on my 71 Adventurer and I've come across a loose end, literally. I have found a plug end looking for somplace to go, and it seems from my wiring diagram to be for the brake sentinel. Anyone got a clue as to what this is and where I might find it?

[Dok]

That plugs into the brake proportioning valve. Follow the brake lines exiting the master cylinder, stright down and inside the C channel of the frame. On the proportioning valve, you will see a silver lug on top, press the connector onto that lug.
Brad