I use a remote reading thermometer and a hair dryer. I unplug the fridge and put the sending unit for the thermometer and the hair dryer in the fresh food compartment. I heat the inside to about 100 degrees, close it up, then let it sit for about 8-12 hours. When I open the door there is usually a pool of water in the bottom on the inside of the fridge. That means the coil drain thawed out and it is now draining properly.
A lot of refrigerators actually drain the coil into the inside in the fresh food compartment down the back wall into the bottom of the food bin where from there it drains into the drip pan.
The newer stuff is quite different from the old.
This one, for example, has no external coils.
I was surprised by that - on my old fridge, I kept a spray bottle full of water, and if it was hot or seemed the fridge was working too hard, I’d spray the coils.
Can’t do that with this one!
our 4 yr old fridge does this - draining to the bottom drawer freezer where it collects - In the summer when it is humid, we have to lay towels in the bottom otherwise it overflows onto the wood floor...Ive noticed it does this much less in the winter when the air is dryer...Ive vacuumed the coils -, & cleaned everything yet it persists