I have the hard drive cooling fans on the inside of the refer and it really helps to keep the frost off the fins and maintain even temps in the unit. I use 2 of the two fan units like
this on the inside fins. Same thing as on ebay, but $10 cheaper. In the back of the refer, I put a fan in the chimney to exhaust the heat. Need to do everything you can to keep it cool in the FL heat and humidity. I can maintain the refer at 33 degrees in the hottest temps here and the freezer and ice maker work like a charm.