I had this problem in the past but since I followed this: http://talk.maemo.org/showthread.php?t=64191 I don't have this problem anymore, I'm almost sure that it is related: This mod will make mce no longer use the light sensor for calibrating screen brightness (I and many other found that annoying) but it also deactivate the notification leds calibration, the leds are now very bright in the dark. I think that the feint led is caused by mce which think that the N900 is in the total darkness which in fact is in your pocket, so it will feint your leds and make them invisible when you take your N900 out of your pocket.