Washer Fluid Level Switch: Description and Operation

Fig.28 Washer Reservoir:

The washer fluid level switch is a single pole, single throw reed-type switch mounted near the front of the washer reservoir, above the two washer pump/motors. Only the molded plastic switch mounting flange and connector receptacle are visible when the switch is installed in the reservoir. A short nipple formation extends from the inner surface of the switch mounting flange, and a barb on the nipple near the switch mounting flange is press-fit into a rubber grommet seal installed in the mounting hole of the reservoir. A small plastic float pivots on the end of a bracket that extends from the switch nipple formation. Within the float is a small magnet, which actuates the reed switch. The washer fluid level switch cannot be adjusted or repaired. If faulty or damaged, the switch must be replaced.

The washer fluid level switch uses a pivoting, oblong float to monitor the level of the washer fluid in the washer reservoir. The float contains a small magnet. When the float pivots, the changing proximity of its magnetic field will cause the contacts of the small, stationary reed switch to open or close. When the fluid level in the washer reservoir is at or above the float level, the float moves to a vertical position and the switch contacts open. When the fluid level in the washer reservoir falls below the pivoting float, the float moves to a horizontal position and the switch contacts close. The switch is connected to the vehicle electrical system through a dedicated take out and connector of the headlamp and dash wire harness. The switch is grounded at all times through another take out of the headlamp and dash wire harness with a single eyelet terminal connector that is secured under a ground screw to the top of the left front fender wheel housing in the engine compartment. When the switch closes, it provides a ground path for the ElectroMechanical Instrument Cluster (EMIC) through the low washer fluid sense circuit. The EMIC uses this input and internal programming to determine when to illuminate the washer fluid indicator lamp. Diagnosis of the washer fluid level switch is included with the diagnosis for the washer fluid indicator lamp. (Refer to INSTRUMENT CLUSTER/WASHER FLUID INDICATOR - DIAGNOSIS AND TESTING).