Whenever I have my heater on I get this knocking inside the center of the dash (like inside the two center vents) but it isn't constant. Only when the Jeep vibrates a little more when I'm stopped at a light or something. It really sounds like the fan is knocking. Anyone else having this problem?

 

not positive that this is your problem, but you may want to pull your glove box and see if something fell down where the fan is. to remove the box, just open it, remove the contents (not required, but it makes it a bit easier), then squeeze the sides until the little stops on the sides clear the dash and allow the door to swing out all the way. once you open it so far the hinge will disconnect and allow you to remove the box completely. this will give you access to your blower and let you see if something fell down there. if not, take this opportunity to check to make sure nothing is loose with the blower and hopefully you will find your problem. good luck

 

you have to turn the temp down a bit, it's too hot for the chipmunks.

 

I'll try that tomorrow morning. I had no idea I could remove the whole box. Thanks for the info.

 

What did you find? Mine started grinding today, but still blows hot. It may be a bad blower. It's an 07 w 36k mi. Maybe chrysler will cover? Wishful thinking.