Washer Fluid Level Indicator: Description and Operation

A washer fluid indicator is standard equipment on all instrument clusters. The washer fluid indicator consists of the text "lowash", which appears in place of the odometer/trip odometer information in the Vacuum-Fluorescent Display (VFD) of the instrument cluster. The VFD is part of the cluster electronic circuit board, and is visible through a cutout located near the lower edge of the speedometer dial face in the instrument cluster. The dark outer layer of the overlay prevents the VFD from being clearly visible when it is not illuminated. The text message "lowash" appears in the same blue-green color and at the same lighting level as the odometer/trip odometer information through the translucent outer layer of the overlay when it is illuminated by 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 the instrument cluster electronic circuit board based upon cluster programming and a hard wired input received by the cluster from the washer fluid level switch mounted on the washer reservoir. The washer fluid indicator function of the Vacuum Fluorescent Display (VFD) 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 LED will always be off when the ignition switch is in any position except ON or Start. The instrument cluster will turn ON the washer fluid indicator for the following reasons:

- Washer Fluid Level Switch Input - Each time the cluster detects ground on the low washer fluid sense circuit (washer fluid level switch closed = washer fluid level low) the cluster applies an algorithm to confirm that the input is correct and not the result of fluid sloshing in the washer reservoir. The cluster tests the status of the circuit about seven milliseconds after ignition ON, and about once every second thereafter, then uses an internal counter to count up or down. When the counter accumulates thirty ground inputs on the circuit, the washer fluid indicator will be illuminated. If the vehicle is not moving when the washer fluid level switch input counter reaches thirty, the VFD will repeatedly and sequentially cycle its indication in two second intervals with the odometer/trip odometer information, the low washer fluid warning, and any other active warnings including: door ajar, gate ajar, and glass ajar. If the vehicle is moving, or once the cluster of a non-moving vehicle receives an electronic vehicle speed message from the Powertrain Control Module (PCM) indicating a speed greater than zero, the warning sequence will consist of three complete display cycles, then revert to only the odometer/trip odometer display Once the washer fluid indicator warning has completed, the washer fluid indicator is extinguished and will not repeat until the ignition switch is cycled.

The instrument cluster continually monitors the washer fluid level switch in the washer reservoir to determine the status of the washer fluid level. 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 and circuits can be diagnosed using conventional diagnostic tools and methods. The washer fluid level switch also features a 3.3 kilohm diagnostic resistor connected in parallel between the switch input and output to provide the cluster with verification that the low washer fluid sense circuit is not open or shorted. This input can be monitored using a DRBIII scan tool. Refer to the appropriate diagnostic information.