Washer Fluid Level Indicator: Description and Operation

A washer fluid indicator is standard equipment on all instrument clusters. The washer fluid indicator is located near the upper edge of the instrument cluster overlay, to the left of center. The washer fluid indicator consists of a stencil-like cutout of the words "LOW WASH" 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 lens behind the cutout in the opaque layer of the overlay causes the "LOW WASH" text to appear in amber through the translucent outer layer of the overlay when the indicator is illuminated from behind by a Light Emitting Diode (LED) 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 when the fluid level in the washer fluid reservoir is low. This indicator is controlled by a transistor on the instrument cluster electronic circuit board based upon cluster programming and a hard wired washer fluid level switch input to the cluster. The washer fluid indicator Light Emitting Diode (LED) receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (run-start) circuit whenever the ignition switch is in the ON or Start positions; 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.

- Washer Fluid Level Switch Input - Immediately after the bulb test, if the cluster senses ground on the washer fluid switch sense circuit for more than about thirty seconds, it turns ON the washer fluid indicator. Any time after the bulb test, the cluster must sense ground on the washer fluid switch sense circuit for more than about sixty seconds before it turns ON the indicator. Once illuminated, the indicator will remain illuminated until the ignition switch is cycled and the cluster senses an open circuit on the low washer fluid sense input. This strategy is intended to reduce the effect that fluid sloshing within the washer reservoir can have on reliable indicator operation.

- 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 bulb check portion of the test to confirm the functionality of the LED and the cluster control circuitry.

The washer fluid level switch is connected in series between ground and the washer fluid switch sense input to the instrument cluster. For more information on the washer fluid level switch,(Refer to WIPERS/WASHERS/WASHER FLUID LEVEL SWITCH - OPERATION). For further diagnosis of the washer fluid indicator or the instrument cluster circuitry that controls the indicator, (Refer to INSTRUMENT CLUSTER - DIAGNOSIS AND TESTING). The washer fluid level switch input to the cluster can be diagnosed using conventional diagnostic tools and methods.