As per the subject line - I am guessing this has to be a defrost drain issue. But I cannot find any instructions on how to remove the defrost control panel cover (on the 'ceiling' of the refrigerator compartment) to check the drain line that leads from there into the back wall. All information I can find suggests checking the drain line leading into the drain pan, but to me that makes no sense. I am pretty sure that something - be that ice or debris - is clogging the drainage line at the 'beginning' if the drain system, not the 'end'.

Am I missing something? Could this be from improper/malfunctioning auto defrost? If so, how do I force a defrost session to see if that stops the water collecting in the bottom of the fridge? Should that be what I start with first?

There was some ice accumulation on the back wall panel in the freezer, for what that information is worth. I did chip that away. We do have an ice maker, but water is not running down from it onto the back wall of the fridge.

I really think I should be able to do some DIY investigation before automatically calling a repair service. I just am not sure where to begin.

Help and thanks.