I had the same problem with my fridge. 50f+ on hot days and would freeze on cool nights. Several trips to dealer , works fine, rv fridges dont work as well as home units " BS every time.
Installed one of these. A manually adjusted resistor to replace a obvious out of spec temperature controlled variable resistor " THERMISTOR " to control temp.
Dometic Thermistor 2931863035 Repair RM2612 52 2812 52 | eBay
Took about 10 min including finding tools and clean up. I wired it in just as instructions indicated. It was 102 f today clear skies and enough wind to preclude awning, fridge held 34f all day. Fridge has always held 34 to 38 with out freezing at night since change over in spring of 14. Pay back was the first 2 week outing with no spoiled food.
I have no connection with vendor.