Rattling noise when heat/AC on??

Whenever I have the heat or AC on LOW or Medium LOW the truck makes a quiet rattling noise from what seems like the passenger side.... I've never had this noise in any other vehicle and really need it to be fixed as it drive me absolutely mad. Has anyone heard this on their Tacoma's or ever heard of this problem before? How about a fix for it?? The truck is an '11 v6 double cab sr5 if it matters.

Thanks in advance to anyone who may know or have words of wisdom about this! -Alex

 

I have the same problem newly bought 05 Tacoma. Boy, I'm glad it's just not an old issue.

 

Had this same issue. Took it to the dealership and had 5 guys try to hear it but they were all too deaf to hear it. Finally they took my word for it and replaced my blower motor and no more noise.