[GreggA]

This may be a case of too much information too fast. This is a side by side model bought in 2000. Long story short - I removed rear panel in freezer when there was a large amount of frost forming and fresh food compartment and freezer were getting warmer. After some research on your site and others, determined I should try replacing the thermistor on the top - bought the part and went to replace. However, it appears there aren't any thermistors. Am I correct in assuming thermistor's weren't used prior to 2002 with GE/Hotpoints? If not, did the fridge rely solely on the defrost thermostat to start thedefrost cycle and should I just replace? I'm not savvy on electrical, but am somewhat mechanical and feel I could handle that replacement. Thanks for your help!!

[denman]

Here are your parts
Replacement parts for General Electric CSX22GRBKAA Refrigerator | AppliancePartsPros.com

I am assuming that the evaporator coils were frosted up to the point that the evaporator fan cannot pull air through them.
You therefore have diagnosed it as a defrost problem.

Am I correct in assuming thermistor's weren't used prior to 2002 with GE/Hotpoints?
It depends on the model not the year.
They were not used in your unit. A thermostat (Item 424 in Section 3 controls your temperatures.This is a very good thing, just take a look through the posts and you will see a multitude of problems with GE units that use a control board and thermistors.

Now for your defrost problem.
First remove the evaporator cover in the freezer so you can see the coils.
Do not let them de-ice.

If yes.
Manually force a defrost cycle by turning the defrost timer cam (Item 257 in Section 3) till the fans and compressor turn off.
There is usually a hole in the cover to let you do this without taking anything apart.
Now check the defrost heater to see if it is on.
Be careful you do not want to burn your fingers.
If the heater is on then the timer needs replacing, re: it is probably stalling during it's rotation so is never getting into a defrost cycle.

If not on.
Unplug the unit.
Remove the wire for one side of the heating element (Item 230 in Section 2) from the wiring and measure it for continuity, usually around 20 ohms or so.

If the heater is OK
Remove one wire to the defrost thermostat (Item 240 in Section 2) and measure it, should be 0 ohms when frozen. Note that it opens just above freezing so must be frozen to check it. Also inspect it, if it is bulged at all replace it even if it measures OK.

If both the above are OK then odds are the defrost timer contacts are toast.
Best way to test this is a live test to see if you have 120 volts across the heater/defrost thermostat combo.

Note: If you click on a part's picture a new page will open with more info and sometimes a Q&A section.

[GreggA]

Thanks denman for the quick and very detailed response. I turned the defrost timer and the fan shut off but the heater didn't come on....after unplugging the appliance, I took the heater out and it looked like a burnt out light bulb!! I did check the continuity and there was nothing....I've ordered both the defrost heater and thermostat as I might as well replace at the same time. Thanks again for your help - this is a great site with very helpful staff!!