Having an ongoing issue since purchased it a few years ago. Blower motor will intermittently stop. Dealer claims the control head needs to be replaced. They say a new one is not available from GM so they installed a used one. Guess what. It worked for 2 miles and quit also. Then it comes back on, etc. Also, sometimes when this happens, the driver side door does not open by using the button - it has to be opened manually. Now the passenger window does not fully open. Any ideas?