I had exactly same problem with GE Arctica PSS27SGNABS model GD403931 about 6 years old. I changed mother board and sensers but that didn't help, so finaly I found on the web solution it was replacing damper that lets in cold air.

An easy check damper function is worth while. A bad damper can put too much cold air in the fridge and is a common issue for "too cold on fridge side".

1. Remove light bulb a cover from inside top of fridge.
2. Get a flashlight and look down the cold air feed hole behind where the bulb was.
3. Hold all 4 "colder" & "warmer" buttons for 3 seconds and the display will flash "0" on freezer and "0" on fridge.
4. Use the temp buttons to set the freezr side to a "1". Fridge should still have a "0".
5. When you have (1-0) hit the turbo button.
The damper should open and close and make a slight motor noise. You should be able to see it open/close with a flashlight down the hole. Repeat as needed.
7. Set the code to (1-6) and hit "turbo" to exit the test mode.

I purchased a used side x side freezer fridge and bought the same problem discribed.
Model PSS27NHMDCC
Serial number RA424514
It sounds like I may have a cold air damper issue.
Frozen food and beverage in the fridge. Set point at 40.
Actual temp at 29 and freezzing everything but the beer.
Problem is, I cannot seem to see down the pastic housing and view the damper working. In fact, i don't see anything but a cold air channel.
Is this model/SN different?
Any suggestions how to check and repair.
Thanks
Not so Handyguy on this one:)

Revised: Took frig air channnels out and found air damper, broken of course. Superglued damper door and frig is workign great. Food is cold not frozen and the beer is great.
Handeeguy

I replaced that damper door one time when my GE Arctica PSS27SGNABS was about 8 years old. Silly little plastic post that swings the door open broke and the door just kind of layed over and would not close. It was a moderately complex fix. Newer assembly had a metal swivel post and have had no issues with that since.