The exterior lights are not fused. Instead, each bulb (or LED assembly) is electronically controlled by the SAMs. When the SAM detects an improper current draw, such as with a bad bulb or a short, it shuts down the circuit. This makes it impossible to check voltage output on socket with a meter. With SDS, you can activate individual bulbs for testing. I'd visually inspect the socket and wiring for any obvious problems like corrosion, rodent chewing, etc.
So if you swap bulbs side to side, the right side still does not work? That will rule out a bad bulb. If the wiring and socket look good, it could be a bad SAM. I assume you are also getting an error on the instrument cluster? If not, that points to a bad SAM.
Rear SAM controls the rear lights. But I just realized something: The rear park lights are LEDs. The LED light bar is used for both park lights and brake lights. The replaceable bulbs are only for the fog lights and turn signals.
It's part of the rear fuse panel, under the storage compartment behind the right seat. But don't go throwing parts at this! I'd recommend either getting your own SDS setup or finding someone who has it to check it out. If you want to trace and check wires, here's the wiring diagram:
Obviously you need to disconnect both batteries before working with the SAM to prevent shorts and damage form electrical surges. It looks like it's the "Black with Green stripe" wire that connects to pin 32 of connector #4 on the SAM. Connector #4 is the largest one.