Great. I just figured out how to fix that problem on my 08 after the dealer replaced the blower motor twice. Planning to trade it on a 14 soon and hope my new one doesn't have the issue you guys are seeing!
I checked and there doesn't appear to be a service bulletin for that issue on the 14s. Hopefully the blower motor does the trick for you. Good luck!
My '14 Summit 11/6 build date had a bad bearing in blower motor. It would let out a high pitched squeal only when on highest blower speed (7). Turn down a notch to 6 and it disappeared. Dealer replaced blower motor. Problem gone.