Internal wires for defrost heater is covered by freezer air duct, you need to disassemble
freezer air duct to check it.

Remove all freezer drawers.

Remove all glass shelves.

Unscrew the screws on air duct.

a. Check the freezer air duct to find the three screw covers.

b. Remove the screw covers (total of three) on the air duct with slotted screw driver.

c. Unscrew all three screws with Cross- head screw driver.

Dismantle the air duct.

a. Catch the bottom of air duct and pull down the air duct.

b. Pay attention to the connectors when pulling out the air duct.

d. Disconnect the terminal for fan motor.
Disconnect the terminal for freezer temp. sensor.

e. Move the air duct out of the freezer compartment.

Check if wires of defrost heater are broken or not.

Disconnect terminal of heater.

Unscrew the two screws with 6mm Philips driver.

Cut off the fastening strap.

Take out the holding foam.

Loosen heater fastening clips.

Lift evaporator with heater up 20mm. Bottom of evaporator must be higher than the edge of water trough.

Remove the heater.

Reverse steps above to reinstall the heater.

WARNING:
Make sure not to deform pipes in red square below during step 5 to step 7.

Power on the appliance and perform a leakage test.

Make sure the sealing sponges are in good condition.

When reinstalling the air duct, fasten the wires to avoid crushing with air duct.

Install the top side first when installing the air duct.

After pushing air duct into place, you should hear a clicking sound. If not, repeat again.

Check to see if there is
a wide gap between air duct and cabinet. If there is, reinstall air duct.