I have an old Admiral NT21B8SA that is destined to become a kegerator assuming I can get this defrost problem fixed. It started with the typical cold freezer / warm fresh food compartment. I took it apart enough to see tons of ice around the coils and blocking the vent to the FFC.

The defrost heater is the kind with a coil through a glass tube. large sections of the glass have been broken (I assume from the expanding ice?) and the coil is exposed so I figured that was the culprit. Just for S's and G's I tested resistance on it and lo and behold it passed so I moved on to the next part.

I tested the bi-metal thermostat which passed continuity tests when cold and failed when warm. This is expected behavior, I think.

At that point I moved on to the defrost timer. The timer has a common post and 3 others. For the sake of explaining this we'll call them 1,2 and 3. When in cooling mode I got continuity on C1 and C2. After advancing the dial till I heard the click, I got continuity on C2 and C3. So, I feel like the defrost timer is working (or at least there's continuity in both defrost and non-defrost settings). At this point I got a little ballsy and bypassed the thermostat and advanced the timer to the defrost position. The heating element was glowing red from end to end.

So, after the long winded description here are my questions:

1) Could it be that the timer has continuity in defrost and non-defrost settings but whatever the mechanism is that normally advances the timer between the settings on it's own is faulty?

2) How important is that glass on the heating element? It seems to work without it. If the purpose of the glass is to protect the element from corrosion, could I get by without it until it failed and replace it then? I guess what I'm trying to figure out is if it's dangerous to have the element exposed (fire risk etc)

Thanks in advance to anyone who responds