I have a 2007 Silverado (new body style) and when I'm using the blower for heating or AC I have been having issues. When I go on a longer drive 30 minutes or more the motor heats up and stops blowing. It works fine before that but suddenly starts vibrating and stops blowing at full speed. It shoots a little air out but not like it should (like if I have it on high, it comes out like it's barely on low). I was told by the dealership that I have to replace the entire blower motor. I wanted to see if anyone else has had this problem and figured out what was going on.