Probably just a spill. You should be able to pop them out by taking the ash tray out and getting behind them and pushing. Sorry I have never tried it but if that doesn't work you would have to either pry them or take out the console which would seem a bit overkill. Our 02 had this same problem due to a juice spill and I just squirted some glass cleaner in there and pushed the buttons a lot. I was in a rush or might of tried a bit harder. I also may be thinking of the e39 so it might not be as easy to pop the buttons out of the X? Either way I doubt you will need to replace them.

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2008 ///M5 - Black Sapphire Metallic/Black Perforated Merino/Madeiro Walnut trim/6-spd Manual
2005 X5 4.8is - LeMans Blue/Black Nappa/Anthracite trim | born 05/20/05 - For Sale
2003 ///M5 - LeMans Blue/Black Interior/Aluminum trim/6-spd Manual - retired
2002 525i - Jet Black/Black Sport/5-spd Manual - retired
2002 X5 3.0i - Sterling Gray Metallic/Tan Leather Sport/5-spd Manual - retired