I have a 690 with the fresh food at 40.The temp reading on the display said 34 another thermometer was at 40. I ran diagnostics found no error codes the thermistors were reading the correct temp. 40and 32 at the evap. When out of diagnostics the temp reading on the display was 34. I removed power to the frig for several mins. plugged back in and the temp reading was correct at 42. The refrigerator starting to cool just fine. Checked both resistance on the thermistors both checked good, so I changed the control board. The next day I get a call from customer that the Frig is again at 40. When I arrived the frig display was at 36 but actual temp was 40, again no error codes so I unplugged frig plugged back in the displayed temp read the correct temp of 40. At this point I changed the frig thermistor again the same problem.
Does anybody have any ideas???
No ice on the evaporator its clean. Compressor pressure on low side was at 19lbs