I bought a 2001 S40 in March of last year and the cigarette outlet worked for about a year. I went to my local Volvo store to get it fixed and they cleaned it out and replaced it. It worked for exactly a day and then it went out again. Could this mean that the outlet is not the problem, that it is something else that has to do with the internal electronics of the car?

 

Not that I've read. Usually it's something simple causing the problem. First thing I'd do is check the fuse. If that is good and the outlet does not have power then I'd check the wiring to the outlet itself. It could have come loose when your dealer did the work.