The mechanism is operational. It moves when I lock and unlock, both with the remote and manually, but the latch remains unengaged. The "door ajar" light on the dash also stays lit. From what I've read elsewhere, it appears I need to remove the back panel as there is no inside hatch release. It's also been suggested to take it to a car wash to thaw out the latch area but I doubt that'll make a difference as the mechanism seems to be moving freely. Can anyone offer a solution? Or what is the procedure to remove the hatch panel? Help will be most appreciated.

If you can hear it lock and unlock with the remote and the key also turns fully each way the rod going to the lock is most likely off.

 

The rear panel will pop off at the top.  There are about 10 of the push in plastic pins that will pop out of the hole if you pull it straight back.

 

The panel will not come all the way off as there are also retainers on the bottom lip of the panel.  You should be able able to pull it back far enough to see the lock.

Ok thanks! I'll give it a go. I did read that suggestion somewhere. Was hoping for another solution because it's so cold here I anticipate breaking some of those pins. But I have a couple heaters so I'll try to warm it up as best I can

K got it open no prob. But I need a PDF diagram of the latch assembly to get it back together properly.

All good now. Thank you! All it really needed was lubrication!