Bosch SHX46A Repair Manual

6.2 Troubleshooting
6.2.1 Heater diagnosing
Test programs heat the water to 150ºF at ~ 2ºF / minute. To
save time, don't run the entire test – when water circulates and
the heater is on, measure the incoming current to the dishwasher.
If the current is ~ 11A, the heater is OK. If the current is ~ 1.5 –
2A, the control or heater could be faulty.
At the control or heater, measure the voltage between the large
red heater wire and a chassis ground or the dw neutral (WHRD
on/off switch or flow switch wire). If the voltage is 120 VAC, the
control is OK. If the voltage is 0, the heater relay has failed –
replace the control.
To check the heater, turn off the dishwasher, block up the tank
and check the resistance of each part of the heater as follows.
 Heater ~ 11 Ω
 Hi-Limit ~ .3 Ω
 Flow switch ~ .4Ω. A spring
loaded plunger closes it when water
is flowing, so you must remove the
microswitch from the heater and
close its contacts to measure the
resistance.
TIP: Current can be measured through the red heater wire at the
control or heater (~ 9.5A). There can be more than one red wire,
so check the wiring diagram to select the heater wire.
NOTE: Open door to run test program for fully-integrated models.
6.2.2 Controls timing out and showing “1”
Occasionally dishwashers can run for hours, not finish washing &
show a “1” in the display. This means the module has timed out
due to an unidentified heating problem -- all heating related parts
must be checked until the problem is found.
Heating system checklist if controls time out:
 Check control module heater relay & solder joints.
 Check wire harness & terminals (to control and heater).
Controls have been replaced when the problem was loose
connections.
 Check heater resistance (~ 11).
 Check flow switch (~ 0.4). If flow switch is OK & water
doesn’t flow, check circulation pump.
 Check NTC (~ 55k @72ºF) and Hi-Limit. See NTC
resistance chart (section 6.3.3).
IMPORTANT: Whenever a “1” shows in the control display, reset
the control after fixing the heating problem by running the
dishwasher. The module resets after the 1st run.
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Flow
switch

Bosch SHX46A Specifications

General

Brand	Bosch
Model	SHX46A
Category	Dishwasher
Language	English