This vacuum door lock switch was used in GM cars, particularly from 1962 to 1968/69 when the systems switched to electric actuators.  This particular switch can be found for sure in 1966 and 1967 Rivieras with standard interiors (only).  The switches mount on the door panel itself.  This may fit a variety of Cadillacs, Chevrolets, Pontiacs, Buicks, and Oldsmobiles where the switches are on the door panel.   

I've tested this switch... it holds vacuum well; see photo with vacuum pump to show it.     Given the direction that the hose ports face, this would've been used on the driver side (left).  You'd have to switch the direction to use on the passenger side.

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