Recently there was excessive moisture inside on the on bottom of our
20+ year old Sears fridge.
Initially attributed it to recent warmer more humid weather.
However turned out that the defrost drain WAS blocked. And defrost was
running down inside.
Not looking forward to emptying at least the freezer compartment,
undoing various screws and dismantling etc. was fortunately able to
reach the end of the drain pipe which rest into a plastic container
mounted on the coils on the back, without moving the fridge; and blow
up it. Which dislodged the obstruction.
Worked fine since.
So just a tip that might work in some cases?