Okay, electrical problem got me stumped

well, to start it's been a long time since I've posted but, here goes. The other day I was out driving and my dome lights decided they didn't want to turn off for some reason. I have tried everything short of getting a fluke and checking voltages. I've unplugged the interior motion sensors and the dome lights so the battery won't drain. Isn't it nice how they're all on one circuit. Anyway, kinda makes me curious as to why this is happening, short of taking it in under warranty, anyone have any idea of what is happening, or know of someone this has happened to? I've spent the time on search already, but nothing to do with this problem that I've seen has come up. And yes, I did plug it in several times just to check to make sure it wasn't something stupid like a door being partially opened. I suppose it could be a bad door sensor (?). Any help is appreciated. And yes, I surf through here pretty regularly still, I'm more a lurker then a poster. I pm people more then anything. Also, no heavy mods on my car. I haven't done much of anything other then exhaust and a cai/tuner from Brenspeed. Once again, thanks in advance.

lol good call on the dimmer switch, that was probably first thing I checked, kinda like an idiot check. The trunk definitly isn't open because the computer isn't saying anything about it, and it's pretty secure last I checked. Guess I'll be taking it into Ford tomorrow. The good thing is it should be warranty covered. Weird thing is though, with constant voltage you'd think the interior motion sensors would always be on. Did I mention I drove it for about 2 hours during daylight with the interior lights on? Those buggers get hot after awhile. I dunno if there is supposed to be a 30 minute timer or not, but if there is, it's definitly passing that one by. Might have to get that looked at as well. Thanks for the help, but it looks like a call to the dealership is in order.