Dakota 2WD V8-4.7L VIN J (2005)
Washer Fluid Level Indicator: Description and Operation
A washer fluid indicator is standard equipment on all instrument clusters. This indicator is located in the center of the speedometer, in the area below and
to the left of the speedometer needle hub.
The washer fluid indicator consists of a stencil-like cutout of the International Control and Display Symbol Icon for "Windscreen Washer Fluid Level" in
the opaque layer of the instrument cluster overlay. The dark outer layer of the overlay prevents the indicator from being clearly visible when it is not
illuminated. An amber Light Emitting Diode (LED) behind the cutout in the opaque layer of the overlay causes the icon to appear in amber through the
translucent outer layer of the overlay when the indicator is illuminated from behind by the LED, which is soldered onto the instrument cluster electronic
circuit board. The washer fluid indicator is serviced as a unit with the instrument cluster.
The washer fluid indicator gives an indication to the vehicle operator that the fluid level in the washer reservoir is low. This indicator is controlled by a
transistor on the instrument cluster circuit board based upon cluster programming and electronic messages received by the cluster from the Front Control
Module (FCM) (also known as the Integrated Power Module/IPM or Power Distribution Center/PDC) over the Controller Area Network (CAN) data
bus.
The washer fluid indicator is completely controlled by the instrument cluster logic circuit, and that logic will only allow this indicator to operate when
the instrument cluster receives a battery current input on the fused ignition switch output (run-start) circuit. Therefore, the indicator will always be off
when the ignition switch is in any position except On or Start. The LED only illuminates when it is provided a path to ground by the instrument cluster
transistor. The instrument cluster will turn on the washer fluid indicator for the following reasons:
-
Bulb Test - Each time the ignition switch is turned to the On position the washer fluid indicator is illuminated for about two seconds as a bulb
test.
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Washer Fluid Indicator Lamp-On Message - Each time the cluster receives a washer fluid indicator lamp-on message from the FCM indicating
that a low washer condition has been detected for sixty consecutive seconds, the washer fluid indicator is illuminated and a single chime tone is
sounded. The indicator remains illuminated until the cluster receives a washer fluid indicator lamp-off message for sixty consecutive seconds
from the FCM or until the ignition switch is turned to the Off position, whichever occurs first. The chime tone feature will only repeat during the
same ignition cycle if the washer fluid indicator is cycled off and then on again by the appropriate washer fluid lamp messages from the FCM.
-
Actuator Test - Each time the cluster is put through the actuator test, the washer fluid indicator will be turned on, then off again during the LED
portion of the test to confirm the functionality of the LED and the cluster control circuitry.
The FCM continually monitors the washer fluid level switch in the washer reservoir to determine the level of the washer fluid. The FCM then sends the
proper lamp-on and lamp-off messages to the instrument cluster. For further diagnosis of the washer fluid indicator or the instrument cluster circuitry that
controls the indicator, refer to testing.
For proper diagnosis of the washer fluid level switch, the FCM, the CAN data bus, or the electronic message inputs to the instrument cluster that control
the washer fluid indicator, a diagnostic scan tool is required.
