Rear hatch does not lock

It sounds like the lock actuator is not working but to be sure lets see if it is getting power when you work the locks. Here is a guide to help you see how check both wires:

https://www.2carpros.com/articles/how-to-use-a-test-light-circuit-tester

You must remove the door panel.

https://www.2carpros.com/articles/door-panel-removal

If you have power at the lock actuator replace it with new. Here is how it will be for your car.

Check out the diagrams (below). Please let us know what happens.

Cheers, Ken