Freezer Defrost Tube Heater Kit

Second time in about two months, and it's never done it before in the 19+years we've had it.
Several good YouTube videos on replacing the "Heat Probe", though generally for newer models. You can probably figure it out, though.
Unplug the 'fridge
1. empty the freezer
2. take out the shelf and ice maker (three screws w/ 1/4" nut driver)
3. remove the "floor" of the freezer (two screws w/ 1/4" nut driver)
4. remove the back of the freezer (two screws w/ 1/4" nut drive)
You will see ice buildup in the drip tray and in the drain hole. That's the problem.
This is probably a ton of ice under the freezer floor. I used a thin metal spatula to pry up the sheets of ice, up to the metal drip tray.
I used a heat gun (a hair dryer would probably work) to thaw the ice around the drip try and pry it out. Don't over heat anything. Take your time. Don't melt anything other than the ice and do that slowly.
Be VERY careful around the fins and refrigeration tubes.
It took about an hour to get all the ice out except for the iced up drain hole.
Boiled some water and carefully poured it on the ice in the hole. Blot out the melted ice with a sponge or paper towel. Do this over and over until the ice is about a half inch below the lip, still plugging hole.
Use a turkey baster or a funnel with a piece of hose and keep pouring hot water into the drain hole. The baster is good because you can not only add the water, you can suck out the melt water.
Keep doing this until you start hearing water draining into the drip tray underneath the 'fridge. The drain hole is now clear.
Wrap the heat probe around the black tube under the refrigeration coils and fins and insert the tab into the hole.
Crimp the heat probe tightly around the black tube and attach it tightly with the screw.
NOTE: My refrigerated did not come of a heat probe originally and the kit did NOT come with an attachment screw, so I had to improvise. If you are replacing you probe, save the screw.
Reassemble the freezer in reverse order of disassembly. Hooking the ice maker back up is a royal PITA. And make sure you attach the little grounding wire to the tab on the back panel before you attach the panel.
Plug the refrigerator back in. The ice maker won't work until the freezer is cold enough to make ice again. That will take several hours.

Unclogging the drain was not the main problem. The cause was the problem. Back panel in back of freezer was rusting over the years, and rust and pieces of paint were clogging the drain. Would have had continuing problem. Sanded all the rusted areas on back of panel, and then covered them with strips of duct tape, and reassembled. rust wont break loose and clog the drain. That is the permanent fix! Tape prevents droppings that clogged drain. Pieces of rust and paint clogging drain was the cause, nothing more. Checked tape, and it's doing it's job, and holding tightly, even with freezing and moisture. Fixed for another 19 years. Part was not necessary so far. Rust over the years was the problem. Sorry, but this doesn't sell parts, does it?