If all your other door locks are working it's most likely the wiring harness between the roof and rear hatch. There is a rubber boot that protects the harness between the roof and hatch but the wires inside become brittle over time and eventually crack. To repair mine I pulled the boot out of the roof side and cut it with a razor a few inches and rolled it up to expose the broken wires, stripped the insulation off the broken wires, and then used some crimp connectors on them. I had three broken wires altogether. Put the boot back and wrapped some electrical tape on it. Has worked fine ever since. Good luck!