I have an update in the Avalanche saga. They called. Actually, they called my husband several times while he was at work. When he went down to the dealership they told him they had seen my complaint on Yelp! (yay!) and wanted to know what they could do to make it right. So, now the Avalanche is in the service department and my husband is driving a pretty nice courtesy car. Hopefully, they can (and will) fix the problem.