Parked in Barstow, CA with our Montana 5th wheel a couple years ago in 100 degree temp. AC would run a few minutes then shut down. Have a plastic spray device that hooks onto a water hose. Put that on the roof pointed at the condenser and turned on the water. AC unit stayed running and the water helped to remove the heat from inside the trailer.
Found out later that the duct to the bedroom did not have an end so that much of the cool air entered the "attic" then out the roof vents. Cut a pool noodle wide enough to fit snugly into the duct down stream from the bedroom AC vent. The result was much more air flow into the bedroom and a noticeable improvement on cooling throughout the trailer.