Defrost Heater; Evaporator Thermistor; Defrost Overtemperature Thermostat - GE ZIC36ON Series Technical Service Manual

Defrost Heater

Caution: Use care to avoid scratching the finish
on unit walls.
The defrost heater is a single-calrod type, radiant
heater mounted under the evaporator.
To remove the defrost heater:
1. Remove the drawer (see procedure).
2. Remove upper right slide/support assembly by
removing 3 Phillips screws.
3. Remove lower right slide/support assembly by
removing 3 Torx screws.
4. Remove 5 screws, disconnect light and light
thermostat wiring, and remove rear duct.
5. Remove 4 screws and evaporator cover.
6. Disconnect the heater lead wires.
7. Remove the clip securing the heater to the
evaporator and remove the heater.

Evaporator Thermistor

The evaporator thermistor is mounted on the
upper left side of the evaporator. The defrost cycle
will terminate when the main control board detects
45 °F from the evaporator thermistor. The main
control board must sense 45 °F in less than 40
minutes, or the defrost cycle will time out. Average
time to defrost is 20 minutes. Defrost time should
not exceed 40 minutes. Defrost time does not
include dwell and post dwell periods.

Defrost Overtemperature Thermostat

The defrost overtemperature thermostat (bimetal
switch) is mounted on the evaporator and provides
overtemperature protection during defrost. This
thermostat will open at 65 °F and will close
at 45 °F.
Note: The main control board will not know if the
heater does not come on due to a broken heater,
open defrost overtemperature thermostat, or open
wiring harness. The defrost heater is controlled by
maximum time on the main control board or
temperature at the evaporator thermistor.
Screws
Screws
Evaporator Thermistor
Defrost Heater
Defrost Overtemperature Thermostat
– 21 –
P0003407
P0003343
Clip
P0003343