Service Manual

3-12
n
18” & 24” ADA Built-In Dishwashers
TESTING
For Service Technician Use Only
Thermistor
The thermistor is located under the tub and is aached to the
back side of the sump with two screws. See Figure 1.
Figure 1 - Location of Thermistor
During the hot wash cycle, the thermistor senses the water
temperature and turns the heang element o.
NOTE: If the thermistor is not operang, the hot wash cycle
will set a default me for the heang element to cycle.
Test Procedure
This test will check the wiring to the Thermistor, the control
board, and the thermistor itself. The following items are part
of the Thermistor circuit.
n Harness/Connecon
n Thermistor
n Control Board
1. Check the operaon of the Thermistor in Service Mode.
(See “note” on step #2 on Service Mode Chart, page 2-3.)
2. Unplug dishwasher or disconnect power.
3. Remove access panel. Remove control board cover to
access control board.
4. 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.
5. Disconnect CN4 from the Control Board.
6. Using an ohmmeter, measure resistance between CN4-
2 (GND) and CN4-7 (RE). The following table provides
approximate room and hot water temperatures and their
associated resistance values.
TEMP °F (°C) RES RANGE k ohms
77° F (25° C) 10k ohms
140° F (60° C) 3k ohms
NOTE: All thermistor resistance measurements must be
made while dishwasher is unplugged or disconnected
from power and connector CN4 removed from control.
¾ If the thermistor resistance does not agree with the
table, replace the Thermistor.
¾ If an open circuit is detected, check connecons and
harness connuity between control and thermistor. If
good, replace the thermistor.
¾ If the thermistor resistance is OK , the thermistor is
good. Replace the control board and retest.
7. Unplug dishwasher or disconnect power.
8. Reassemble all parts and panels.
9. Plug in dishwasher or reconnect power and run Service
Mode Test to verify repair.
STRIP CIRCUIT - THERMISTOR
Figure 2 - Thermistor Circuit
CONTROL BOARD
THERMISTOR
CONTROL BOARD
CN4-2
CN4-7
T
THERMISTOR
77°F (25°C) = 10 k ohms
(RE)
BU
PL
(GND)
WARNING
Electrical Shock Hazard
Disconnect power before servicing.
Failure to do so can result in death or
electrical shock.
Replace all parts and panels before operating.