My Samsung French door fridge model RF260BEAESG/AA had cooling issue 6 months after warranty expired! It started with water under crisper drawer and fresh food section temperature got to 60F. I called Samsung service department and was told to turn energy saver off, raise the front one inch and manually defrost the fresh food section by pressing two control keys. Few weeks later the problem came back. I took the rear panel off and found ice was all over evaporator and drain hole. I added long T shape metal to keep drain hole from frozen. A couple of month later the problem came back again. Every couple of month I had to take rear panel off. I heard of adding flexible heater and decided to try. Bought a Gemline GH-203 heater and wrapped around the top part of evaporator. Boy it really works. Never have cooling issue again!
Adding heater can create electrical and fire hazard if is not done correctly. I am a retired electrical engineer and have technical knowledge.