It over-rides the timer that holds the doors open for a set period of time before they close automatically. The door close control is over-ridden when the door is held open by something or someone blocking them, as all elevators are required to have some type of sensor to detect this condition, or if the door open button is being pressed.

I believe the "close doors" button gives people a measure of control. Elevators force us to be in a tiny space and since people are generally impatient the close door button speeds things up.

I hear a sense of frustration behind the question. I work in a building where only one of the 3 elevators seems to have a 'Close Door' button that is actually connected to the doors. 'I share your pain.' I have worked in and visited buildings where these buttons actually work in the elevators, so the quick answer to your question is 'Yes, they actually do something'. That being said, I believe that when building managers or elevator technicians get the message that the 'Close Door' buttons are not working, they don't assign it any kind of priority for repair as it is not an 'essential' function. I do not work in building management or in elevator maintenance, so the foregoing is not given as a piece of authoritative information. I also believe that there is a minimum amount of time that is programmed into the elevators before the doors are allowed to close and that this minimum time can be quite long or quite short, depending on how the elevator has been set up. Again, this is based on personal observation only. I share your frustration and hope that you don't get too wound up when the buttons do not work. Patience is a virtue, but sometimes virtues can be pretty hard to put into gear.

I read somewhere that only something like 1/3 of all the elevators in the country actually have the "close doors" button connected.

It actually immediately closes the door! I use it all the time; unless, of course, someone is approaching the elevator.

I work in elevator manufacturing business. The Close Door buttons are supposed to work if there are no obstruction blocking the closing door (person, hand, etc) making resistance of the action. Some operate on a delay response opposed to immediate close. And yes, I suppose some are not repaired promptly because of the low priority to everyday use. The button does figure into the scheme of things during system checks, fire, and emergency operations though, so they are not to be taken lightly. In this case the doors operate on a different circuit than everyday use. Just because they don't work under normal use doesn't mean that they won't work under special conditions that are on a maintenance list for periodic check.

I thought it did... :-)

"Here's the official line from Australia, but since everything there is upside down, I'm not sure it applies in the Northern Hemisphere. Otis elevator Door Close button. Finally the truth comes out. Yes, the door close button is connected. Yes, it does not do anything when pressed. It was designed to operate when the elevator is switched to "independent service." In this mode the elevator doors stay open until the Door Close button is pushed. Often used when [movers] are shifting furniture or when moving VIPs around, as when in this mode the outside calls do not cause the elevator to stop. Fact, from ex-Otis elevator serviceman and installer." Source and further information: http://www.sdreader.com/php/ma_show.php?id=314 (this article contains some different, interesting theories about the issue. (including the placebo theory)

Good question! I have seen it close the doors quicker on some of the elevators that had very slow closing doors.

haha. no it actually works, trust me. I once stayed in a hotel that's elevator took about 2 and 1/2 min to close. The time ACTUALLY went faster (like 5 sec.) for it to close when i pushed the close door button... yep