I have a intermittent problem with my 8yr old frence door MD#RFG298AA The temps will be fine then next day upper section will go to 70 degrees and freezer to 32 On my screen it is set at 36 fridge and -2 freezer and no codes come up After 8hrs or so, fridge will be back to normal. I simulate door closed with magnet and fan kicks on and cold air is coming in. I think it might be a thermostat or is there a timer in defrost mode? Any answers would help. Had a repair guy come out said it was working fine which it was at that time he could not bring up a code so $70 bucks and he leaves still broke!!!!