trouble with defrost mechanism

When I last posted we narrowed my issue down to something faulty with the defrost mechanism. The coils had a thin coating of frost/ice and the blades of the fan were stuck in thick ice. After freeing the fan blades and powering up the fridge, the fan worked. It was explained that there are three components to the defrost mechanism that might be to blame. Any thoughts on which part is most likely? Thanks.

Number 11 in the picture below is the defrost heater. It is a glass tube with a filament running through it. That is the most likely to be faulty. Do you have a meter to test continuity through it with?

Thanks Ninja, if its just continuity I can test. Do you know the cost of that part, and is it a difficult access? I have been able to get as far as the coils.

It is mounted in the middle of the coils, so you are right there. It is very easy to replace if you find it open, showing no continuity. That heater is available at the link below. Let me know what you find!

http://www.appliancepartspros.com/ge-heater-defrost-wr51x10027-ap2071519.html

love that I have continuity on the more expensive of the parts. The long glass filament is intact and has continuity. I don’t remember the other two options. One I think was a defrost timer? I would feel more comfortable following your advice. Thanks again, so far so good!

That is correct. There is a thermostat that opens to prevent the heater from overheating. It is mounted in the same area of the coils, and the defrost timer, mounted in the control section. The thermostat will typically show damage (they expand and look blown up), but not always. If that thermostat looks okay, it can be tested but the coils need to be cold. You will need to turn the refrigerator on for a couple hours prior to testing. If it tests closed (shows continuity through it), the timer is bad. If you find that to be the case, the timer is available at the link below. Let me know what you find.

http://www.appliancepartspros.com/ge-10hr-35min-timer-wr9x483-ap2061693.html

Awesome. I found and removed the timer in the control section. Nothing visibly obvious with the thermostat, although you said that’s not always the case. Is it time to buy a cheap multimeter to continue diagnosing this issue? Would I be looking for a digital or analog model.

A meter is always a good investment, I prefer a digital. They are available for around $20 or so. In your case, I suspect that the timer is indeed faulty. You can test it without a meter by letting the refrigerator run for a couple hours, then manually advance the timer (the little round, plastic knob on it, turn slowly clockwise until the refrigerator shuts off) and see if the heater heats up. If it does, then we know the heater and thermostat are both good, leaving only the timer.

Forgot to mention earlier that I tried to determine if there was continuity across the leads that connect either end of the heater filament. My findings were that there was no continuity whether unplugged from the wall or plugged in. Again, the filament has continuity, the wiring connected to it doesn’t. As regards to a plastic knob on the timer I do not see a moveable part exposed. There is a small adjustment wheel that could be turned with a very small flat screwdriver. If not that I will likely just order a new timer and see if that does it. Thanks.

Yes, turn that little plastic adjuster to initiate a defrost cycle. I suspect replacing the timer will remedy the problem, though.