One problem related to blower has been reported for the 2005 GMC Envoy. The most recently reported issues are listed below.
I turned on the defroster on a cold evening in a GMC Envoy I had rented from national rent a car. It was, I believe, a 2005 model. It was a cold night and the defroster had to be turned on. While driving, five minutes later, a large "crack" was noted. The windshield cracked starting in the exact shape of the central defroster. The single exit defroster is a hazard as heat is too concentrated.