Does anyone know anything about how this foglight switch physically
works?

I have encountered the following problem:

- fog lights wouldn't shut off (green light stays on whether switch is
up or down)
- by smacking the switch with my hand it will turn off the fog lights
(sometimes)

So, I checked for loose wiring. Nope.

Then I noticed the little light bulb that sits on top of the switch
was loose (it must have come un-screwed). So I took it out. The
switch works 100%. I put the light bulb back in and give it a twist
and the fog lights never shut off. The light bulb is 100% working.

Has anyone ran into this before? How could a working light bulb
somehow bypass the switch and leave the foglights on? Is it possible
that the other light bulb (switch illumination) is causing this? Is
the switch defective? Is the lightbulb defective?

Definitely weird, no?