Lower part of refrigerator warm

Pulled refrigerator plug from socket.
Removed all freezer items. Put them into sink to keep cool.
Phillips head screwdriver removed screws from plastic housing fan cover from rear of freezer compartment.
Removed fan housing panel by lifting up and out. Panel has two small tabs that fit into back panel.
Removed back panel with phillips head screwdriver.
Fan is now exposed. Not working.
Plugged power cord back in.
Disconnected power adapter to fan.
Voltage meter sees power to ground and hot wire.
Fan not working
Unplugged power cord.
Removed fan from rear by socket tool.
Used hair dryer to remove ice build up in styrofoam insert between freezer compartment and lower section.
Removed foam insert....broke a couple of pieces off.
Test new motor with a line cord wire stripped at ends
Motor works. (Old one did not work with same test)
Replaced fan into bracket.
Replaced bracket into rear of freezer.
Plugged power cord in.
Fan does not work.....Whoa!!!..closed freezer door and heard fan running!!! It works.
Replaced everything...foam insert, panels, food.
One week later, still working.....
(Now...I don't know why the fan did not start right away...it may be that there's a small round thermostat sitting on a copper tubing, that needed some time to kick in...but that's a supposition.)
Have fun