Maybe I'm lucky, but my refrigerator is bone stock and has been working perfectly, without any mods, for 18 months. Outside air temperature has been in the range of 13F to 95F with humidity from very low to 100%.
My freezer temp is in the single digits except when the cooling unit is defrosting which is every 46 hours per Norcold information. The refrigerator is always in the 30's.
No fan mod needed here.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof