My rig is a 14 Denali, started it up and pressed the power button the the HVAC controls and the screen was blank, nothing turned on, was just blank. Being in TX the AC is on all the time, so I turn off the HVAC when I park it and back on when I start it up again. It's never done this before. After sitting for over 2 hrs, I started it up and the HVAC powered back on like normal. WTF? Has anyone had this happen before? Do I have a fuse that's going out? Some software that needs updating?