I’ve been living in this house for the last few months with a few roommates. I believe the house is about a hundred years old and for the last several years has been inhabited primarily by college students, so it has some character. I sleep upstairs, in a room with doors that go to the attic space. A few nights ago I noticed a strange glow coming from the corner of the frame on one of the attic doors. Upon closer inspection I realized it was a small green light which had been painted over with white paint. This was the first time I had noticed it glowing. After some investigating I determined that the light was turned on by a switch downstairs. I made a comic about it. So, does anyone have any idea what this light was originally used for?
Here is a cite for The Green Light
I like your comic!
Not really sure what your light was for, however the house built by my great grandfather in the late 1880s was wired at some point after the town got electricity, and there was a switchpanel [the pushbutton type, pairs of buttons, one for on and one for off instead of rockers or flip switches] with 16 pairs of switches. You could turn on almost every light in the house except for the attic and basement at more or less one time. It may have been some sort of ‘butler’s light’? If that room had been the butler or maid of all work’s room, it would indicate that someone who had just come home late at night needed them for something.
Perhaps it is a signal light to let whoever slept in that room know that the last person coming home was in and safe…you flip the switch when you get home, and then Mom & Dad know you’re home safe. We have a sort of similar setup in our house, but not specifically for that…it just worked out that way. All the lights in the house can be controlled by two master panels, one at the side door and one in my parents’ bedroom. When a light is on, an indicator light on the panel glows red. When my sister and I would be out late babysitting, my parents could go to bed and leave the side porch light on for us. When we came home, we’d turn the light out, and the tiny light in my parents’ room would go out. When they awakened during the night, they didn’t have to wonder if we were home or not, they could just turn their head and see if the red light was glowing.
I have never seen this light switch system, or the push-button switches we have, anywhere else, ever. I’ve seen round, old-fashioned push-button light switches, but ours are big black rectangles.
Or, it was a childrens’ nightlight, that the parents could turn on for them.
It probably isn’t escalator trolls. 
I also loved your comic.
a lot of these old houses had things built in them by the original owner’s that seemed important to them but make no sense whatsoever to us.
You’ve got an awesome style. 
Are there any more comics of yours online?
It’s the signal light for the Tardis, obviously (serious guess: remnants of a home security system or fire alarm system that’s since been de-installed?).