Dometic refrig. questions

we have what I assume is a 2011 Dometic refrig. as the Rv is a 2011. The fridge is a single door outfit with an inner door on the freezer compartment. It is in a slide-out so the upper vent is in a sidewall rather than the roof. I suspected that this arrangement might not be as effective as a roof vent. The refrigerator is mounted inboard about 10 inches from the wall of the slide. This leaves a "box" behind the fridge that measures about 48 inch high, 20 inch wide, and 10 inch deep. The typical vents are located top and bottom of this box. Just above the lower vent a "shelf " is mounted in a half-assed attempt to direct the cooling air past the coils. I had planned to mount fan(s) in the "box" to help with cooling the coils but ran out of time. I did, however, install the little computer type fan inside the fridge.
A recent campout at a racetrack in Nebraska( no connections - no shade ) put this arrangement to the test. It did fare well. The fins in the freezer section iced over but the cooler section did not stay cool enough. We need to store medicine above freezing but below a certain temperature. At times the cooler temps. were at the max. allowed.
The fridge has a display panel with LEDs ( from 1 to 5) indicating cooling ranges. we had this set at 5. I just today noticed that the fridge also has a clip-on sensor on the fins in the cooler section. It was mounted at the bottom of the fin. I guess my question is - Would moving the sensor up on the fin have caused the unit to cool the lower part better? Would I have been able to then change the temp selector to maybe 4 LEDs and keep the freezer fins from icing up? Remember, I had the small fan circulating the air in the lower section.