refrigerator not staying cool

[7kelly7]

I have a ge profile artica that the fridge will not go below 40 degrees. I took back panel off back of freezer and it was froze up, I defrosted and reset and it still didn’t raise the fridge temp. the coils haven’t froze up again either. I replaced fridge thermistor and it didn’t help. I am wondering if the fan is the problem. it runs but if it has multiple speeds then maybe it is in slow speed? any help appreciated! thanks