Product review (4 stars): Works so far.
I had to replace the defrost heaters, the thermocouple and defrost timer to get my 30 year old GE frig back up and running.  The defrost heaters were burnt black and the original defrost timer, had a sparking issue on the copper clocking tines on the inside of it, as I did take the original 30 year old one apart to see what had happened to it.  I just changed out the thermocouple to be safe, as I did not have a multimeter to test it to see if it was good or not.  My frig is back cooling like it should be, but I will have to wait and see if this lasts as long as the original parts.  If you replace your defrost timer, make sure you use a slotted screw driver to start the defrost cycle before you plug in the frig again, to see if the defrost heaters are working properly before putting everything back together.  The part numbers for the replacement will be different than your original defrost timer, so don't be alarmed that you ordered the wrong part number.