KitchenAid 2003 M Technical Education page 78

COMPONENT
Not running.
Not running up to speed.
Open evaporator fan feedback circuit.
Evaporator Fan
Frost blocking evaporator air flow.
Improper wiring.
Noisy.
Inoperative.
Freezer (FC)
Thermistor
Reversed wiring.
Not operational.
Inverter
Compressor not operational.
RC = Refrigerator Compartment
FC = Freezer Compartment
SYMPTOM
6-8
TEST PROCEDURE/ACTION
Run control diagnostics to check the evapo-
rator fan operation in step 3. The evaporator
fan receives voltage from the main control
board. Voltage should be present at pins 1,
2, 6, & 7 of connector 7 of the main control
board during operation (see the diagram on
page 7-2). A failed evaporator fan motor or
any condition that can mimic a failed motor
will cause the control to run the compressor
100% at 4500 rpm. If voltage is still present
and the evaporator fan is still not operating,
verify evaporator fan jumper harness wiring
(see "Evaporator Fan-Improper Wiring" sec-
tion below). If corrosion is present on the
terminals, replace the evaporator fan jumper
harness.
Run control diagnostics to check the defrost
system operation in step 7. The test mode
can be used for a manual defrost cycle to
clear the coil. A frost load as the result of
one or more doors being left open and can
take several days to clear.
Verify the wires connecting from the square
connector of the evaporator fan jumper har-
ness to the bimetal harness. WH/V to WH,
YL/BU to BU, YL/BK to YL, and YL/RD to
RD. If wiring is incorrect, order evaporator
fan kit.
Binding—Check for the evap fan to be mis-
aligned and for the wire harness to be pull-
ing on the evap fan.
Hitting—Check for the fan blade hitting the
scroll and realign.
Check wires and connectors. Thermistor
may be out of range. Run control diagnostics
to check the FC thermistor operation in step
1. Check resistance given in the diagram on
page 7-2. If the thermistor circuit is open, the
control will initiate default run time to hold
temps until service can be performed.
Although extremely remote, the thermistor
wires can be reversed in the connector at
the main control boards. A quick way to con-
firm this is to remove the FC thermistor,
initiate control diagnostics and look for a "2"
in step 1, which is an indication of an open
circuit for the FC thermistor.
Check for voltage from the main control
board to the inverter: 3 to 6 VDC on pins 3 &
8 of connector 7.
Check for voltage from the inverter to the
compressor. Input voltage to compressor is
0.02 to 5.5 VDC. Ohm the compressor. Re-
sistance should be 6 to 7 Ω.