Did the same repair as in your video, still have issues with the drain freezing solid.

I replaced the heater and the sensor and I am still getting leaks. It looks like I received the same replacement heater you all used. Where the wire from the left side has its own harness. The OEM heater’s left side wire is connected with the right to go into the same wire harness. In your video at the 8 minute mark you all cut and go to the finishing steps. Before that, the left wire is still sitting unconnected. After 8 minutes it is connected. Did you all splice the wire? I spliced it into the empty spot on the harness/connector that was on the right wire. I do not have co2 so I used hot water/hair drier to the point of it flowing freely. At the end you talk about sealing the wall plate//fan unit up against the fridge. I am worried because the Styrofoam/tape is damaged on mine. That may cause leakage, but still the bottom freezes solid and stops draining. (I checked the ohms on the heater and it is not burnt out)
Any advice would be great. I am thinking of ordering the thermal fuse at this point because it is the only part I have not replaced.