This GE side by side Profile series, about 12 years old, is cooling poorly. I used "ACME how to" web site to trouble shoot the problem. Got down to the timer switch which proved defective on testing. Replaced it. Thought the problem solved. Cooled better at first. Within a day or so the best temp in freezer was 20 degrees. More ice was also noted on the rear panel. When the panel was removed the bottom third of the evaporator coils, those between the two heater elements, were cased in ice. Retested new switch. It seems to be okay. Retested heater elements. I get continuity. According to some resources there should be some resistance. Went to the parts store and tested a new set of elements. Got the same reading. I am confused and frustrated. Help!

On our fridge there was a radiator thingy underneath that got jammed with dust and lint. We vacuumed it out and the fridge worked much better.

If evaperator coil was iced up you have one of two problems, low refrigeriant or lack of air flow. If refrigeriant is R12 (and it probably is) you will need refrigeration mechanic.