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Fresh Food Evaporator Thermistor
The fresh food evaporator thermistor (part #
WR55X10025) is located in an aluminum ther-
mal block on the back of the evaporator. It is
attached to the fresh food evaporator by a wire
tie. See
Fresh Food Evaporator
instructions.
If the fresh food evaporator thermistor is either
open or shorted, the main control board defaults
to a fixed defrost cycle of 1 hour at high speed
fan.
Barbs on the molded housing hold the
thermistor in the thermal block.
Replacement
Should the evaporator thermistor require
replacement, splice a new thermistor into the
harness using plastic bell connectors (part #
WR01X10466). Fill the connector with RTV102
silicone as shown in the illustration.
Insert the new thermistor into the thermal block.
Add RTV102 silicone to hold the thermistor in
place. Make certain to wire tie the thermal block
back to the evaporator.
for accessing
A variable speed
12 VDC motor
is mounted in
front of the fresh
food evaporator.
The fan and
evaporator cover
are replaced
as a complete
assembly.
When activated, the fresh food evaporator fan
recirculates the air in the fresh food compart-
ment, providing cooling independent of the
freezer evaporator fan.
The main control board gathers information from
the fresh food thermistors to determine when,
and at what speed, fan operation should occur.
A constant 13.6 VDC is provided to the fan from
the main control board and switching occurs on
the neutral side. Speed is regulated by pulse
width modulation on the common side of the fan.
When operating, the common side of the circuit
is pulsed open and closed. This pulsing pro-
duces effective voltage being received at the
motor, which is equivalent to a reduction in
voltage. Fan speed is selected and maintained
by the main control board regulating the length
and frequency of the 13.6 VDC pulse.
– 19 –
Fresh Food Evaporator Fan
13.6 VDC
12 VDC
0 VDC
High Speed (12 VDC measured)
13.6 VDC
10 VDC
0 VDC
Medium Speed (10 VDC measured)
13.6 VDC
9 VDC
0 VDC
Low Speed (9 VDC measured)
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