I replaced the defrost timer.same result. tested heater and thermostat,both o k .I replaced them any way,the parts were inexpensive. It still freezes up. some months ago i removed the ice maker, could this be part of the circut?
Here are your parts
Parts for Whirlpool GR9FHMXPS00 Refrigerator - AppliancePartsPros.com
See the attachment for the tech sheet
Defrost should not be part of the ice maker circuit but they may share a connector.
Check out the wiring layout in the tech sheet,.
The next time it freezes over do not defrost it.
Remove the cover in the freezer so you can inspect the evaporator coils.
Turn the defrost timer cam till the fans/compressor go off.
You should now be in a defrost cycle.
Check to see if the defrost heater comes on.
Be careful that you do not burn your fingers.
If it comes on then odds are that there is a probklem with the timer.
GR9FH.pdf (503.1 KB)