Wiper and Washer Systems: Description and Operation

WIPERS/WASHERS

WIPER SYSTEM
The wiper system provides the driver with normal wipe (low and high speeds), intermittent wipe, wipe after wash, and pulse wipe functions. The driver selects the wiper function via a resistive multiplexed stalk switch mounted on the steering column. The low and high speeds are directly controlled via the multifunction switch. The intermittent function is controlled through the intermittent wiper relay and the BCM.

System Features
Speed Sensitive Intermittent Wipe Mode - There are 6 individual delay times with a minimum delay of 1/2 second to a maximum of 18 seconds. When the vehicle speed is under 10 mph, the delay time is doubled providing a range of 1 second to 36 seconds.

Pulse Wipe - When the wiper is in the OFF position and the driver presses the wash button for more than 62 milliseconds, but less than 1/2 second, 1 wipe cycle in low speed mode will be provided.

Wipe After Wash Mode - When the driver presses the wash button for over 1/2 second and then releases it, the wiper will continue to run for 2 additional wiper cycles.

The wiper system utilizes the BCM to provide intermittent operation. The low and high speed are run directly from the multifunction switch. The BCM controls the intermittent relay to change the wiper delay as the multifunction switch input changes. The BCM uses vehicle speed input to double the usual delay times below 10 mph.

Operation
The windshield wipers will only operate when the ignition switch is in the ACCESSORY or IGNITION RUN position. Fuses, located in the instrument panel fuse block protect the circuitry of the wiper system and the vehicle.

The wiper motor has permanent magnet fields. The speeds are determined by current flow to the appropriate set of brushes.

The intermittent wiper system, in addition to low and high speed, has a delay mode.

The delay mode has a range of 0.5 to 18 seconds. The wiper delay times will double to a range of 1 to 36 seconds when the vehicle speed is less than 10 mph. The delay is done by a variable resistor in the wiper switch and a relay. The relay is used for intermittent wiper function only.

The wiper system completes the wipe cycle when the switch is turned OFF. The blades park in the lowest portion of the wipe pattern.

When using the DRB III scan tool, refer to the proper Body Diagnostic Procedures manual.

WASHER SYSTEM
The windshield washer pump is electrically operated. The wash function can be accessed in the OFF position of the wiper control switch. The electric pump assembly is mounted with a grommet directly to the reservoir.

Wash switch must be pressed for at least 0.5 second to get the wipe after wash. Holding the wash button depressed when the switch is in the OFF position will operate the wipers and washer motor pump continuously until the washer button is released. Releasing the button will stop the washer pump but the wipers will complete the current wipe cycle. Followed by an average of two more wipe cycles (±1) before the wipers park and the module turns OFF.

Fluid is gravity fed from the reservoir to the motor. The fluid is forced by the pump through rubber hoses to the wiper arm mounted nozzles which direct the fluid streams to the windshield. The hose assembly has two one way flow check valves located in each hose line. The purpose of the check valves is to improve fluid flow response time and to prevent excessive washer fluid staining the surface of the hood. The wiper arm mounted nozzles evenly distribute washer fluid across the surface of the windshield. The pump and reservoir are serviced as separate assemblies.

WIPER BLADES
The wiper blades are a rubber element with a steel vertebrae that are mounted on the end of the windshield wiper arm and sweep across the front windshield to clear it of water, snow, and debris.

When the wiper blade rubber element is exposed to the weather for a long period of time, it tends to lose wiping ability. Periodic cleaning of the wiper blade element is suggested to remove the accumulation of salt and road film. The wiper blades, arms, and windshield should be cleaned with a sponge or cloth and a mild detergent or non-abrasive cleaner. If the blades continue to streak or smear, they should be replaced. The driver blade element is 600 mm in length and the passenger blade element is 550 mm in length.