Similar problem and I have read the post re: check timer, check thermostat, check heater.

I removed the cover and found the coils Frozen solid, so I can assume that there is a defrost problem. The little fan that blows cold air to the fridge section Does work.

I have a GE pds22sbrbrss, bottom freezer, and my understanding is that the Defrost Timer is on the main circuit board. Since there is no way to "manually" set the timer, can I assume that the odds of this being the problem, is slim and that I should move onto the thermostat and heater?

If so, Gene posted to check the Resistance across the heater.

My question is this. The wires to the heater, lead to, what I assume, the thermostat (small metal cylinder, about 1/4 height of a "c" battery). The wire connection between the heater and thermostat seem to be soldered and "shrink" wrapped(no quick connect). Do you suggest that I physically cut the 2 wires that go to the heater then test for continuity? Assuming the answer is Yes, and I find that there IS continuity, then the heater is still good,..... I can therefore assume now that the thermostat is defective.

Lastly, I'm assuming that unless the thermostat is Frozen, that it is difficult to check for continuity across the thermostat. Again, I assume that I would have to physically "cut" the wires between the Thermostat and heater to check for continuity.

thanking you in advance.
P