– 20 –
The ambient thermistor is located under the top
interface. The thermistor clips into the backside
of the top interface and is used to determine the
offset temperature of the refrigerator.
The offset temperature is the temperature the
main control targets. Air temperature inside a
compartment is typically lower than the thermistor
reading due to cabinet thermistors proximity to
cabinet walls. The main control increases the
offset temperature when the ambient temperature
increases.
To access the thermistor, place the top interface
in the service position (see
Top Interface
Removal
, under
Top Interface
in this section of
the service guide).
To test or replace the thermistor, follow the steps
in the
Thermistors
section of this service guide.
The Humidity board is located under the center
of the top interface. The humidity sensor on
the board provides the main board with relative
humidity percentages based on the feedback
voltage (see table below). The feedback voltage
will range between 1 to 4 VDC. The relative
humidity percentage is used to determine the
articulating mullion heater on time (the greater the
humidity, the greater the heater run time).
Relative Humidity
Voltage (DC)
20%
1.5 V
50%
2.3 V
80%
3.1 V
Humidity Sensor Board Diagnosing
Before changing the board, ensure the proper
voltages are going to the humidity board.
Humidity sensor voltages can be checked at the
humidity board or main board.
Connector on Humidity Board
• Orange
to
tan
/
black
: 13 VDC
• Orange
to
white
: 13 VDC
• White
or
tan
/
black
to
red
/
white
: 5 VDC
• Yellow
to
red
/
white
: 1 - 4 VDC
NOTE:
0 or 5 VDC from
yellow
to
red
/
white
may indicate a bad humidity sensor. Replace the
humidity board if there are no open or shorted
wires to the board.
Connectors on Main Board
• J4 pin 4 (
orange
) to J4 pin 5 (
tan
/
black
): 13
VDC
• J4 pin 4 (
orange
) to J2 pin 3 (
white
/
silver
):
13 VDC
• J5 pin 5 (
red
/
white
) to J4 pin 5 (
tan
/
black
) or
J2 pin 3 (
white
/
silver
): 5 VDC
• J5 pin 5 (
red
/
white
) to J5 pin 6 (
yellow
/
white
): 1 - 4 VDC
NOTE:
0 or 5 VDC from J5 pin 5 to J5 pin 6 may
indicate a bad humidity sensor. Replace the
humidity board if there are no open or shorted
wires to the board.
The RJ45 connector is mounted to the humidity
sensor board inside the top interface and is only
available with the humidity sensor board. The
RJ45 connector is the access point to update
software using a software update module (SUM)
or connect a service diagnostic tool.
Humidity Sensor Board Removal
1. Place the top interface in the service position
(see
Top Interface Removal
, under
Top
Interface
in this section of the service guide).
2. Remove one 1/4 in. hex-head screw and
disconnect the wiring harness.
Humidity Sensor Board
RJ45 Connector
Ambient Thermistor
