The "Condenser" is a strange term on an RV fridge, it does not exactly have one.. And what it has instead is SUPPOSED to get warm (heat exchanger).
On many Trailers and quite a few motor homes as well the power distribution panel has both 12 volt fuses and 120 volt breakers behind a single last door (I say it that way because if said panel is in a cabinet, the cabinet door does not count, only the last door) and the model will likely be plastered on said door (inside perhaps).. one common one on older rigs is the Magnetek 6300 series, which very clearly does not know the lyrics so it hums the 60HZ chorus.
More modern RVs have the Parallex 7300 which I do not know as much about but it too can hum I suspect.
What is huming? The transformer that brings 120 down to around 9 VAC (Do not ask but that's the voltage if you want to end up with 12 DC, I DO know why)
I even know why they hum.
NOTE: IF you have the Magnetek.. Consider an upgrade. Progressive Dynamics makes a drop in replacement for the "Guts" of that beast that is about a thousand times better than the 6300 ever was.
Home is where I park it!