From the '03 service manual:
WASHER FLUID LEVEL
SWITCH
DESCRIPTION
The optional washer fluid level switch is a single
pole, single throw switch that is integral to a unique
version of the washer pump/motor unit, located rearward
facing side of the washer reservoir, which is
located in a dedicated hole on the top of the sump
area near the back of the windshield washer reser-
voir on the right front fender wheel house in the
engine compartment. Only a molded plastic nipple
with a clear vent tube are visible near the top of the
washer pump/motor unit that is equipped with the
optional fluid level switch when it is installed in the
reservoir. The vent tube is routed to and retained in
an integral clip located behind the reservoir filler cap
near the top of the reservoir. This version of the
washer pump/motor unit also has a third terminal
pin in its integral connector receptacle. The washer
fluid level switch cannot be adjusted or repaired. If
faulty or damaged, the entire washer pump/motor
unit must be replaced.
OPERATION
The washer fluid level switch monitors the level of
the washer fluid in the washer reservoir. When the
fluid level in the washer reservoir is at or above the
predetermined minimum, the switch contacts are
open. When the fluid level in the washer reservoir
falls below the predetermined minimum, the switch
contacts of the normally open switch close. The
washer fluid level switch is connected to the vehicle
electrical system through the washer pump/motor
unit take out and connector of the vehicle wire harness.
The switch receives a path to ground at all
times through another take out of the vehicle wire
harness with a single eyelet terminal connector that
is secured under a ground screw located near the
right headlamp in the engine compartment.
The switch is connected in series between ground
and the washer fluid switch sense input to the ElectroMechanical
Instrument Cluster (EMIC). When the
switch closes, the EMIC senses the ground on the
washer fluid switch sense circuit. The EMIC is programmed
to respond to this input by illuminating the
washer fluid indicator. The washer fluid level switch
input to the EMIC may be diagnosed using conventional
diagnostic tools and methods.
