Originally Posted by
MSHardeman
EDIT: BART, I just thought about this; does the rattle happen only when your interior fan is running? If so the fan may be out of balance or hitting something in the dash. Every now and then my fan will go out of whack and contact something back in the dash and make a loud, rhythmic ticking/clacking sound (and it is loud enough to be heard over the music). Luckily it goes away, but I may have to get back there and fix it some day. You said that your rattle happened when the heater was going full blast (lucky dog with all the snow) so that's what made me think of it.