Washer Fluid Level Indicator: Description and Operation

A washer fluid indicator lamp is standard equipment on all instrument clusters. The washer fluid indicator lamp is located near the upper edge of the instrument cluster overlay, in the upper left quadrant of the cluster. The washer fluid indicator lamp consists of a stenciled cutout of the words "LOW WASHER" in the opaque layer of the instrument cluster overlay. The dark outer layer of the cluster overlay prevents the indicator from being clearly visible when the lamp is not illuminated. However, an amber lens behind the cutout in the opaque layer of the cluster overlay causes the "LOW WASHER" text to appear in amber through the translucent outer layer of the overlay when it is illuminated from behind by a replaceable incandescent bulb and bulb holder unit located on the instrument cluster electronic circuit board. The washer fluid indicator lamp is serviced as a unit with the instrument cluster.

The washer fluid indicator lamp gives an indication to the vehicle operator when the fluid level in the washer fluid reservoir is low. This lamp is hard wired on the instrument cluster electronic circuit board, and is controlled by the cluster circuitry based upon cluster programming and a washer fluid level switch input to the cluster. The washer fluid indicator lamp bulb receives battery current on the instrument cluster electronic circuit board through the fused ignition switch output (st-run) circuit whenever the ignition switch is in the ON or Start positions; therefore, the lamp will always be OFF when the ignition switch is in any position except ON or Start. The lamp bulb only illuminates when it is switched to ground by the instrument cluster circuitry. The instrument cluster will turn ON the washer fluid indicator lamp for the following reasons:
- Washer Fluid Level Switch Input - If the cluster senses a ground input on the low washer fluid sense input for more than about thirty seconds, it turns ON the washer fluid indicator lamp. Once illuminated, the lamp will remain illuminated until the cluster senses an open circuit on the low washer fluid sense input for more than about thirty seconds or until the ignition switch is turned to the OFF position, whichever occurs first. This strategy is intended to reduce the effect that fluid sloshing within the washer reservoir can have on reliable lamp indications.
- Actuator Test - Each time the cluster is put through the actuator test, the lamp will be turned ON and OFF in a prescribed sequence to confirm the functionality of the lamp and the cluster circuitry.

The washer fluid level switch is connected in series between ground and the low washer fluid sense input to the instrument cluster. For more information on the washer fluid level switch, (Refer to WIPERS/WASHERS/WASHER FLUID LEVEL SWITCH - DESCRIPTION). For further diagnosis of the washer fluid indicator lamp or the instrument cluster circuitry that controls the lamp, (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.