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Note:
When testing these motors:
• You cannot test with an ohmmeter.
• DC common is not AC common.
• Verify 2 voltage potentials:
a. Red to white - power for internal controller
b. Yellow to white - power for fan
• Observe circuit polarity.
• Motors can be run for short periods using a
9 volt battery. Connect the white wire to the
negative (-) battery terminal only. Connect the
red and yellow wires to the positive (+) battery
terminal.
The evaporator fan motor is positioned between the
front and rear fan motor brackets that are located
behind the evaporator cover. The evaporator cover
must be removed to access the fan motor brackets.
(See
Evaporator
.)
Note the position of the fan blade on the motor
shaft and the locations of the fan motor mounting
grommets.
It is necessary to pull the fan blade off the motor
shaft to remove the two 1/4-in. hex head screws
that hold the front bracket to the rear bracket. A
single wire harness is connected to the fan motor.
When operating, voltage is sent in pulses (much like
a duty cycle) as opposed to an uninterrupted
fl
ow.
This pulsing of 13.6 VDC produces effective voltage
being received at the motor, which is equivalent to a
reduction in voltage.
High Speed (9.5 VDC measured)
Medium Speed (8 VDC measured)
Low Speed (6.5 VDC measured)
12.3 VDC
11.5 VDC
8.2 VDC
13.6 VDC
0 VDC
0 VDC
0 VDC
13.6 VDC
13.6 VDC
Note:
Depending on speed, the effective voltage
may range from 6.5 - 13.6 VDC.
Fan speed is selected and maintained by the main
control board regulating the length and frequency
of the 13.6 VDC pulse. Temperature can cause
some fan speed variation. Fan speed can vary +/-
5%, depending on the temperature, with higher
temperatures causing slightly higher speeds.
The evaporator fan has a 4-wire connection:
White Wire
- DC Common (J2 pin 3)
The white wire is the DC common wire used
for testing. During repairs, DC polarity must be
observed. Reversing the DC polarity causes a
shorted motor and/or board.
Red Wire
- Supply (J2 pin 8)
Each motor uses an internal electronic controller to
operate the motor. Supply voltage from the main
control board remains at a constant 13.6 VDC.
Blue Wire
- Feedback/RPM (J2 pin 1)
On previous Arctica models, the blue wire reported
rpm (speed) information to the main control board
for speed control purposes. On this model, the board
does not require or read any feedback information
from the fan motor.
Yellow Wire
- Signal (J2 pin 4)
The yellow wire is the input wire from the main
control board. The main control board provides
8.2 VDC effective voltage for low speed, 11.5 VDC
effective voltage for medium speed, and 12.3 VDC
effective voltage for high speed. The fan operates
in low speed only when the fresh food thermistor is
satis
fi
ed.
Note:
To prevent excessive vibration and noise,
be sure to install the fan motor grommets in their
original positions.
Front
Bracket
Rear
Bracket