driver side rear door not opening
What may have happened is a plastic door latch rod clip has broken.
If the rod falls out of the latch, the door won’t open from inside or outside.
Tester
There’s a fuse to check. The body control module will contain fault codes for this. Get it scanned before you do anything else. Also these doors are prone to malfunction when the batteries health is marginal. One thing to try after making sure the battery has good health, is to disconnect battery for awhile then reconnect. Also a common failure is the doors wiring harness.