Dometic 12 cu. ft fridge operating temperatures

I have a dometic 12 cu ft fridge and am having trouble maintaining the fresh food area temperature. Had unit plugged in at home for 2 days before we left for our trip and the temp was 34 turned unit onto gas operation. Traveled approx 2.5 hrs to out destination and temp raised up to 37 which is still good. My dw switches from gas to electric and turns the temp setting from the #3 position to #2 (lower the number warmer the temp) after doing this just before we went to bed for the night. In the morning the fridge temp raised to 51 so my dw now turns the temp setting to #4 and only dropped the temp to 47. So now dw turns the temp setting to #5 (coldest) and the temp would drop to 44 but overnight without getting into the fridge the temp raises to 51. So I switched from electric operation to gas and it lowered the temp to 44 but the temp still raises overnight to 51. Needless to say we had to throw out lots of food which spoiled from the high temps. What suggestion do you have in order for me to figure out this problem? The fridge is located in a slideout and I could hear a small fan running in the upper outside fridge vent cover. I have a call into the dealer where we purchased the unit from but of course they haven't returned my phone call yet. This is located in a 2014 Montana so still under warranty but we are about 5hrs from the dealership. Thanks in advance for all of your comments