2015 Equinox - rear hatch suddenly will not open with the button overhead inside, nor will it open with the remote, but when I manually press the latch outside, it unlocks, then immediately closes. It never raises. The only way I can open it is to catch it when it unlocks and manually pull it up. Once up, the only way to close it is manually...the button on the hatch does not close it. I have verified the fuses (#23 and #49) are OK. I also Googled the issue and no help so far. Any suggestions on what to check is appreciated. Thanks.