This is a little late but in case someone references this post in the future. In the OP's case the wiper motor works (because it moves still) but the attached wiper transmission is broken. It's all part of the same assembly.
The transmission is the part that makes the wiper move in both directions and places the wiper in the park position. The rear glass release will not work if the wiper transmission senses the wiper is in the home position. In order to replace the motor/transmission assembly you have to take the interior hatch panel off. To take the interior panel off you need to open the rear window to remove 2 pins. It's a bit of a conundrum.
It is resolved by unfastening the interior panel at the bottom, middle and sides and reaching up and manually pushing the window latch open so you can remove the pins and take the interior panel off completely. Refer to the circled part in the attached photo of the latch mechanism.
I just went through all this and it's not really well documented outside of how to replace the window wiper motor assembly. I didn't understand the relationship between the window motor and glass release but figured it out eventually. I had bought a used wiper motor assembly from a pick n pull which turned out had a bad motor and a good transmission. While the motor didn't work, at least the inoperative glass latch issue was resolved. In the end I moved the transmission to my good motor and was able to resolve my inoperative rear wiper and glass release for $31 CAD and a few hours.
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