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Thermistor
The thermistor is clipped to the inside of the fan housing.
The main control board controls the dampers, fan, and heater based on input from the Climate Control
Drawer’s control board and the thermistor.
Actual drawer temperature will be displayed in Select Temp mode only. The Climate Control Drawer
display will show the selected temperature for approximately 4 seconds after a Select Temp mode has
been selected. After approximately 4 seconds, the actual temperature of the drawer will be displayed.
The actual-temperature display is based on the temperature that the main control board sees from the
thermistor. The selected temperature (example: CITRUS – 43 °F) is based on the logic of the Climate
Control Drawer control board. If the actual temperature that is displayed is incorrect, the thermistor and
main control board are suspect. If the temperature associated with the Select Temp mode is incorrect,
the Climate Control Drawer control board is faulty.
All thermistors can be checked using Diagnostic Mode.
Heater
The 120 VAC heater is located in the fan housing.
The fan housing must be removed from the fresh
food compartment to access the heater.
The heater is controlled by the main control board.
The main control board turns the heater on and off
based on input from the Climate Control Drawer
control board and the thermistor.
EMI/RF
Filter
AC Power
Cord
Brown
Orange
Heater Connector Behind
Climate Control Drawer
Heater
438 Ω
Fan Housing
Heater Connector
Heater
Heater resistance should be 438Ω and can be
checked at 2 places:
• J7-5 to J7-9 at main control board. Connector
J7 should be disconnected from main control
board when checking resistance.
• Heater (2-pin) connector located behind the Climate Control Drawer. Connector should be
disconnected when checking resistance.
The heater can usually be turned on by entering any of the Quick Thaw modes.
120 VAC output to the heater can be checked at 2 places:
• J7-5 to J7-9 at main control board.
• Heater (2-pin) connector located behind the Climate Control Drawer.