If all else is working, then I'd suspect the connections internal to this receptacle have come loose.
Typically all receptacles in an RV are daisy-chained. They use the self-contained style that needs no electrical box and are assembled very rapidly as the romex (115 VAC cable) does not need to be stripped.
I'd do the following:
o turn off power
o Did you turn off the power?
o Check for power at the other receptacles
o remove this receptacle
o Did you turn off the power?
o disassemble the receptacle - there should be tabs on the back:
Once disassembled & the romex removed, make sure nothing is touching the wires, nor are they touching each other... they shouldn't, as they probably have puncture marks from the receptacle pins.
o Turn on the power
o probe for power in the puncture with your meter or test lamp.
o No power? There's a broken wire upstream
o Find the closest receptacle - probably in or under a cabinet.
o Turn off power
o Do it again.
You'll eventually find romex with power.
Good luck; let us know what you find.
