Hi @beach757
Here's a [https://www.youtube.com/watch?v=h4pO6WNZpU8|video] that shows how to replace the drain tube extension, where it exits the cabinet above the drain pan.
Check to see if the defrost meltwater is getting to the pan.
If not, the drain tube inlet is under the evaporator unit, behind a panel inside at the back of the freezer compartment, check that it is not blocked there.
Here's a [https://www.youtube.com/watch?v=iCR2nzkfh-g|video] that shows how to replace the defrost heater that may help. I realize that this isn't the problem but the video shows how to access the evaporator unit as the heater is under it,