Service Manual

TESTING
18” & 24” ADA Built-In Dishwashers
n
3-15
For Service Technician Use Only
Wash Pump
This test will check the wiring to the wash/rinse motor and the
motor itself. The following items are part of the wash/rinse
motor circuit.
n Harness/Connecon
n Wash Pump & Capacitor
n Control Board
Test Procedure
1. Check the tub and sump for anything that may be
impeding water ow. Inspect and if necessary clean the
coarse-lter system. Also, inspect spray arm water nozzles
and clean if needed.
2. Check the wash pump and electrical connecons by
performing the “Service Mode Test” on page 2-3. The
following steps assume that this step was unsuccessful.
3. Unplug dishwasher or disconnect power.
4. Remove access panel. Remove control board cover to
access control board.
5. Lay the dishwasher on its back. Use a small at-blade
screwdriver to unclip snaps around the drip-pan. Remove
drip-pan/oat switch to access under tub components.
6. Unplug connector CON1 and CON2 from control board.
7. Check the wash pump—using an ohmmeter, measure the
resistance across the high and low pump coils as shown in
the following chart.
MOTOR COIL PINOUTS RESISTANCE
High Coil CON2, Pin 2 to CON1, pin 1 44-54 ohms
Low Coil CON2, Pin 3 to CON1, pin 1 69-87 ohms
¾ If the resistance is within range, the wash pump and
harness are good. Go to step 8.
¾ If far outside the range, replace the wash pump.
¾ If an open circuit is detected, check connecons and
harness connuity between control and wash pump. If
good, replace the wash pump.
8. Reconnect CON1 and CON2 to control board.
9. Test Wash Pump High Coil—Set voltmeter to AC and
connect leads to CON2, pin 2 and CON1, pin 1 on the
control board. Plug in dishwasher or reconnect power.
10. Start the Service Mode Test and at the proper step
measure for AC out of the control between CON2-2 and
CON1-1. (Refer to Wash Motor Strip Circuit below.)
¾ If no AC voltage is measured, replace the control board
and retest.
¾ If 120 VAC is measured and wash pump is not running,
go to step 12.
¾ If 120 VAC is measured and wash pump is running, go
to step 14.
11. Unplug dishwasher or disconnect power. Repeat steps 9
and 10 for the Wash Pump Low Coil. Use pinouts CON2-3
and CON1-1.
12. Test the wash pump capacitor. NOTE: A faulty capacitor
may cause the motor to “hum,” not start, or start slowly.
a. Discharge the capacitor by touching the leads of a
20,000 Ω resistor to the two terminals.
b. Disconnect the wires from the capacitor terminals.
c. With an ohmmeter, measure across the terminals and
note reading.
¾ If a steady increase in resistance is noted, capacitor is
good. Replace wash motor assembly and retest.
¾ If the capacitor is either shorted or open, replace
capacitor. and retest.
13. If the preceding steps did not correct the wash/rinse
motor problem, replace the control board.
14. Unplug dishwasher or disconnect power.
15. Reassemble all parts and panels.
16. Plug in dishwasher or reconnect power and run “Service
Mode Test” to verify repair.
DANGER
Electrical Shock Hazard
Only authorized technicians should perform
diagnostic voltage measurements.
After performing voltage measurements,
disconnect power before servicing.
Failure to follow these instructions can result in
death or electrical shock.
STRIP CIRCUIT - WASH PUMP
Figure 2 - Wash Pump Strip Circuit
CONTROL BOARD
WASH PUMP
CONTROL BOARD
L1
CON1-2
N
CON1-1
CON1-1
(N)(N)
THERMAL
140° C
CAP 10 uF
HIGH: ~ 49 Ω
LOW: ~ 76 Ω
CON2-2
CON2-3
BK
BU
YE
MOTOR RELAY HIGH
MOTOR RELAY LOW
BU
RD
BK
YE
BU RD
BU
BR
(ML-H)
(ML-L)
(L)
Wash Pump Ass’y
P
120 VAC
WASH
PUMP