GE PROFILE PDE9900 Technical Service Manual page 16

Detergent Level Sensor
The SmartDispense TM detergent level sensor consists
of a single level detection continuity sensor and
includes the following components:
• a grommet seal
• a low detergent LED indicator light
• a wire harness.
When the detergent in the reservoir drops below
the continuity sensor, a signal is sent to the control
board and the low detergent LED indicator light is
turned on. The light indicates 3 to 7 wash cycles left
before the detergent reservoir is completely empty.
SmartDispense
Light will
turn on LOW DETERGENT
when time
S
ENSING
to refill
W
ASHING
Note: The Low Detergent LED may look like it is
illuminated when in fact it is not. An indicator that is
illuminated will be a bright red.
Note: If the SmartDispense
used, the low detergent light can be turned off (or
on) by pressing the Added Heat pad 5 times within
3 seconds. There will be 3 audible beeps when the
light goes off.
The sensor is similar to the type used in several
automotive applications such as the windshield
wiper fl uid reservoir.
The control takes a reading of the detergent level at
power up (when power is restored from an outage)
and each time the door is closed and latched.
The control outputs a pulsing 5 VDC analog signal
to the sensor and monitors the return voltage.
Changes in the quantity of detergent in the tank
change the amount of current drawn by the sensor.
D
RYING
S
ANITIZED
C
LEAN
TM system is not being
– 16 –
Control 5 VDC to Sensor
The routing of the DC wiring from the tank is very
important. The 3 tape points on the tank keep the
DC wiring perpendicular to the AC harness wiring
running down across the front of the tank. (See tank
photo.)
Tank
Tape Point
Sensor and Gasket
Note: The dispenser tank, sensor with wire harness,
and gasket are only available as a complete
assembly (part # WD35X10058). They are shipped
with a new dispenser tank retaining collar.
Detergent Level Sensor Strip Circuit
DETERGENT
SENSOR
BRN/YELLOW
J4-1
Tape Point
Tape Point
RED
J4-3