[Bruce Parker (RIP)]

The Chev HUW wireless van has 'kill switches' on the rear body doors so that when open the interior lights switch off so the enemy won't see them.

I've been puzzling over how these work, but have enough evidence (pic 1) that they are similar to a closet switch available today (pic 2). These operate with a plunger (which would have to be altered as these switches turn the lights on when the door is open and I need them to turn off). But the real question I have is this: on the HUW these switches are located on the latch side of the door and not the hinge side meaning the back of the door would hit the side of the plunger instead of pushing it so it won't work.

But then I notice two small holes (pic 3) that take threaded screws and are dead centre for the switch plunger (so unlikely used for mounting the switch). The Petawawa HUW (pic 4) even shows a thin metal tab the screws hold in place. So what's going on? Could the tab be a flat spring that bends into the door jamb such the when the door closes the spring tab depresses the switch plunger? Seems strange and prone to breaking. Or am I completely off base and the switches are more like a spring loaded toggles instead of a plunger...but then what's the tab and two screws for? I'd really like to confirm the arrangement with someone who knows or has a photo of an open door with the switch in place.