That hot western sun on the refrigerator side of the trailer is certainly heating up the air space where the outside cooling coils are. This reduces the temperature difference between the coils and the ambient air making it more difficult to exchange the heat from the coils to the outside air. When outside temps (or the temp of the air near the coils) goes above about 85 degrees the efficiency of the refrigerator starts to drop off quite a bit. Getting better airflow over the coils with fans and restricting the air space to Dometic specs certainly helps. Also reducing ambient air temps can help too if possible but about the only thing we can do there short of moving to cooler parts of the country is to provide as much shade on the coil side as possible.
