Wiper and Washer Systems: Description and Operation

Fig.1 Wiper/Washer Switch:

WIPERS/WASHERS
Wiper System
The windshield wiper system is controlled by a switch located on the multi-function switch stalk. The multi-function switch is located on the steering column behind the steering wheel.

The windshield wipers will operate when the ignition switch is in the ACCESSORY or IGNITION ON position. The windshield wipers will return to the parked position when the ignition switch is turned to the OFF position. Fuses, located in the Junction Block and Power Distribution Center protects 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 1/2 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 controlled by a variable resistor in the wiper switch and the Body Control Module (BCM). The BCM controls the timing for the wiper ON/OFF, as well as the wiper HI/LO relay.

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 for Diagnosis and Testing.

Washer System
All models are equipped with electric operated windshield washer pumps. The electric pump assembly is mounted with a grommet directly to the reservoir.

The windshield washer system is controlled by a switch located on the multi-function switch stalk. The multi-function switch is located on the steering column behind the steering wheel.

The wash function can be accessed in the OFF position of the wiper control switch. 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. If the wash switch is pressed momentarily with the wipers in the OFF or INTERMITTENT position, a pulse wipe cycle consisting of two wipes will occur.

Fluid is gravity fed from the reservoir to the motor. The fluid is forced by the pump through rubber hoses to the hood mounted nozzles which direct the fluid streams to the windshield. The one way flow check valves are located in each hood nozzle. 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 hood mounted nozzles distribute washer fluid on the surface of the windshield. The nozzles are adjustable, refer to the Washer Nozzle Adjusting Procedures. 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.