Here's one I have done business with, and found them well-price and responsive:
RV Cooling Unit Warehouse in Memphis TN
Here's two versions of the one for your refer:
Search Results - RV Cooling Unit Warehouse They make the usual rebuilt ones, and also a heavy duty brand new one.
Look at the videos they have posted on their site. You might be surprised how simple it is to replace the 'cooling unit'.
ps: they refund you $100 once you return the original core back to them.
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“Courage is being scared to death, but saddling up anyway.”
...John Wayne...........................