My maytag refrigerator is warm at fridge and I removed the panels at the freezer and found lots of ice at the back and all over the coils. I melted ice with bow dryer and tested defrost heating element its OK. Problem came back again. What more can I check
Thank you guys

Two things come to mind. One is the defrost timer, if you will turn it with a screwdriver or whatever it takes, move it to a different time to defrost, This my make the timer turn easier and could solve the problem.

Second it the circulating motor in the freezer compartment, if they fail the fridge section will fail to get any of the cold air out of the freezer section, making it warmer than it should be. Also the freezer section will not defrost the way it should.

It's either the defrost timer switch or the small motor that circulates the cold air. There isn't much to figuring out which it is. If you don't hear the small circulating motor, then it's that part that went bad. You can buy a replacement motor at a parts store and replace it yourself. (I've done that repair myself and it's quite easy to do). The defrost timer switch is a little bit tricky in that if you have one of the newer model fridges you may have a motherboard that needs to be replaced as there is no separate part for the defrost timer switch. If it's just a regular model, then the part is easily obtainable from a parts store and changed out.