"The freezer seems to be cold enough but not in the lower section."
You don't have a thermometer in both the fresh food section and freezer? Hmmm. Seems like basic RV stuff. Do you have a battery operated fan in the fresh food section?
Winnebago 2101DS TT & 2022 Chevy Silverado 1500 LTZ Z71, WindyNation 300 watt solar-Lossigy 200 AH Lithium battery. Prefer boondocking, USFS, COE, BLM, NPS, TVA, state camps. Bicyclist. 14 yr. Army -11B40 then 11A - (MOS 1542 & 1560) IOBC & IOAC grad