The defrost timer was the problem

Well, crossing my fingers didn't work: the fridge iced up again so obviously more diagnosis was in order.

I figured out that there is an access to the defrost timer on the underside of the module that is attached to the ceiling of the refrigerator compartment. This allows you to manually turn the defrost timer without removing the whole module.

After turning it enough that I could hear a click, the fridge promptly would go into a defrost cycle.

The kill-a-watt told me that the defrost element uses around 460 watts, compared to 160 watts for running the compressor. The defrost cycle takes about .14 KWH (460 watts for 0.3 hour)

Also, when it is in defrost cycle, the compressor is disconnected, so you definitely know that it has switched over.

After 20 minutes the defrost thermostat shuts off, and power consumption goes to about 1 watt.

But the compressor never comes back online... after 20 minutes which is the normal cycle time, the timer is supposed to "click" and turn the compressor back on and shut the defrost element off.

Since the element heats up (if you put your hand in the back of the freezer compartment, you can feel the heat), and it's using 460 watts, we know the defrost element is good.

Since the element shuts off after 20 minutes, we know the defrost thermostat is working.

Therefore, the timer must be bad.

After searching ebay, I found a timer that matched specs (1/2 hp, 12 hour) and looked identical except for the model number, made by the same manufacturer.

In the week while waiting for delivery, I would activate the defrost cycle manually for 20 minutes once a day. (It's interesting that the element would run for just about exactly 20 minutes). I put a mirror up so I could see the little grey thing to turn. It's kinda tricky to get a screwdriver on it.

I just swapped the defrost timer and things seem to be working. Now when I open the fridge and put my head nearby and listen, I can hear the timer motor grinding slowly. Before, I heard no timer motor noise. (edit: I think the timer motor only runs when the compressor runs, so it's quiet when the compressor is shut off. I only heard the timer motor running while the defrost cycle was active.) So that explains why after exactly 12 hours the defrost cycle didn't initiate, it's 12 hours of compressor run time).

It was super easy to swap it out because it was identical in virtually every way, though the case on this one was opaque versus clear plastic.


It's pretty useful to have the kill-a-watt, if this fridge using more KWH than normal, around 1.5 KWH per day, you definitely know something's wrong.

Maybe I'll put some pictures up tomorrow when I feel more industrious.