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Defrost Thermostat
The defrost thermostat (also known as the over-
temperature thermostat) is clipped to the inlet of
the evaporator coil to prevent a runaway state of
defrost. The thermostat is in series line with the
neutral side of the heater. The thermostat will
open when a temperature of approximately 95°F
is reached and close again at approximately 65°F.
Defrost Thermostat Diagnosing
Check for an open defrost circuit. If open, check
the thermostat at the 2 and 6-pin connectors to
verify a thermostat is open and the defrost heater
is not at fault.
J9 to J7 on Main Board:
J9 (blue) to J7 pin 9 (orange): ~35 ohms
If open, check from the pink wire at the defrost
heater to the orange of the 6-pin evaporator
harness connector to verify the thermostat is
open and the defrost heater is not at fault.
Defrost Thermostat Removal/Replacement
1. Remove the icemaker (if installed).
2. Remove the evaporator cover (see
Evaporator Cover Removal under
Evaporator Cover in the Freezer section of
this service guide).
3. Squeeze the sides of the metal retaining clip
to release the clip.
NOTE: The defrost thermostat can be replaced
individually or as part of the evaporator harness.
4. If replacing the thermostat as part of the
evaporator harness, disconnect the 6-pin
cabinet connector and the defrost heater
connectors. If replacing the thermostat by
itself, proceed to the next step.
5. Cut the thermostat wiring as close to the
thermostat as possible.
6. Strip the two wires back 3/16 inch for splicing.
7. Prepare the replacement thermostat by
cutting the wiring 4 inches back from the
thermostat and strip the wires back 3/16 inch.
8. Using two bell connectors (Part #:
WR2X4686D), splice the wiring. After the
fully with silicone grease (Part #: WR97X163).
Silicone Grease
Defrost Heater
The defrost heater is a 33-ohm glass tube style
heater which is mounted to the bottom of the
evaporator coil.
Defrost Heater Diagnosing
J9 to J7 on Main Board:
J9 (blue) to J7 pin 9 (orange): ~35 ohms
If open, check from the terminals of the defrost
heater to verify the heater is open and the defrost
terminator is not at fault.
Defrost Heater Removal
1. Remove the icemaker (if installed).
2. Remove the evaporator cover (see
Evaporator Cover Removal steps).
3. Bend the tabs of the evaporator coil bracket
up.
4. Slide the heater out of the evaporator
coil brackets and disconnect the heater
connections.
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