Check out the schematic at
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Go to "service information" and "webtech" and enter your year and model and click on the "ETM" tab for schematics.
There's been a problem with water getting inside the wiring connectors between the door harness and the in-vehicle harness and corroding the terminals, causing a vairety of issues, but in my experience this is less common than a problem with the door lock actuator itself.
I've seen a couple cars with doors that were replaced due to body damage, and the used door that was installed had the wrong actuator in it.
Furthermore, if you're under 60k miles in the U.S., take it to the dealer and let it be their problem-- you'll still be within the warranty period.