Maytag side-by-side fridge/freezer: Model msd2456deb – fridge stops keeping things cold after 2-3 months of "working".
So the fridge works, for 2-3 months if I do nothing. However, it doesn’t work perfect because it doesn’t keep a good even temp, and some things will get icy… or even frozen (like celery). But, for the most part things aren’t getting frozen, and it just keeps them cold like they should be.
Eventually, though, after 2-3 months, it won’t keep things cold anymore and I have to manually defrost it to "fix" it. I can reach inside the air return, bottom fridge, behind crisper, and I can feel that the coils are iced/frosted over. Defrosting the fridge manually by unplugging it for 24-48 hours "fixes" it and makes it work like normal again. That’s a pain, and not really the "fix" I’m looking for. 
I purchased one of these and plan to put it in, because I read a lot on line and it seems to fix similar problems, and is notorious for going bad and needing replaced: 61005988 Refrigerator Defrost Control Board for Maytag
However, where is the defrost heater and how do I get to it? Could this be causing the problem? Also… is there a fan that sucks the air back into the freezer, and where is that? Could that be the problem and does anyone know the part number? Air should flow from the top of the fridge, back into the freezer at the bottom, correct?
Thanks anyone who can answer!
-Dan