Evaporator is typically inside the freezer, in the back. Not the center
partition. Look in with a flashlight, and see if the back inside of the
freezer has "snow" accumulating. Please let us know what you find.
Is the refrig colder on the bottom, or about the same, bottom and top?
Christopher A. Young
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Check to make sure you didn't change the thermostat setting
I agree that the thermostat is the most likely culprit, but I would
check to make sure the fridge defrost timer isn't stuck in operating
mode before you replace the thermostat.
Basically, the brains of a frost free fridge is the defrost timer. It's
job is to divert electrical power away from the thermostat for about 20
minutes or so once every 20 hours of fridge operating time. The power
is diverted to the defrost heater to melt all the ice that's accumulated
on the evaporator coils.
But, it's only a tiny little motor in the defrost timer, and a bit of
friction can cause it to get stuck; either in defrost mode, or in
operate mode. If it gets stuck in defrost mode, then your fridge
essentially goes into permanent defrost mode until the defrost timer
unsticks. If it gets stuck in operate mode, the fridge will operate
continuously without defrosting itself, and eventually frost will start
forming inside the freezer compartment.
Look on the partition wall between the fridge and freezer sides of your
side-by-side for a removable panel. Behind that panel will be the
evaporator of your fridge, which is the source of all the cold the
fridge makes. It should not be clogged up with frost. You should have
anywhere from no frost to a uniform coating of frost over it's entire
surface. If it is all clogged up with frost, then the fridge is not
defrosting properly, and that could be due to a stuck defrost timer.
If you can see that the evaporator coil isn't clogged up with frost,
than I'd go ahead and replace the fridge thermostat.
PS: Nowadays, the correct term for a fridge "thermostat" is a "cold
control" because it serves a different purpose than a true thermostat.