Wiper and Washer Systems: Description and Operation

WIPER SYSTEM
The wiper system provides the driver with the normal wiper (low and high speeds), intermittent wipe, and wipe after wash. The driver selects the wiper function via the resistive multiplexed stalk switch mounted on the steering column. The BCM uses the input signal from the wiper stalk switch, wiper motor park switch, and the washer switch to control the wiper system. The Body Control Module (BCM) then controls the relays and timing functions to provide the driver selected features.

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 (6 km/h), the delay time is doubled providing a range of 1 second to 36 seconds.

Park After Ignition OFF
Because the wiper relays are powered from the battery the BCM can run the wipers to park after the ignition is turned OFF.

Wipe After Wash
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 wipe cycles.

The wiper system utilizes the BCM to control the ON/OFF and high/low relays for low and high speed wiper functions, intermittent wiper delay as the switch position changes, pulse wipe, wipe after wash mode, and wiper motor park functions. The BCM uses the vehicle speed input to double the usual delay time below 10 mph (17 km/h).

Fig.1 Wiper/Washer Switch Location:

WIPER/WASHERS
Wiper System
The wiper/washer switch is mounted on the right side of the multi-function switch on the steering column, behind the steering wheel.

The wiper system has LOW, HIGH, and INTERMITTENT switch positions. The intermittent wiper system, in addition to low and high speed, has a delay mode and a pulse wipe mode.

The intermittent wiper function is integral to the wiper switch. All electronics and relay are inside the switch assembly. The wiper switch also includes the MIST feature which provides a single wipe when actuated.

The wiper motor is not serviced separately from the motor assembly. The wiper linkage is crimped onto the motor and cannot be detached. If the motor is found faulty, the entire motor assembly must be replaced.

Move the control lever up to select the desired wiper speed. Move the lever upward to the second detent for Low speed wiper operation, or to the third detent for High speed operation.

Use the intermittent wiper when weather conditions make a single wiping cycle, with a variable pause between cycles, desirable. Move the lever to the DEL position, then select the delay interval by turning the end of the lever. The delay can be regulated from a maximum of approximately 18 ± 0.5 seconds between cycles, to a cycle every second ± 0.5 second.

The windshield wipers will only operate with the ignition switch in the ACCESSORY or IGNITION RUN position. The wiper circuit is protected against over loads by a fuse in the fuse block and a circuit breaker within the wiper motor. This protects the circuitry of the wiper system and the vehicle. The wiper motor has permanent magnet fields.

The intermittent wiper delay mode has a range of 1 ± 0.5 to 18 ± 0.5 seconds. Pulse wipe is accomplished by holding stalk lever in the WASH position momentarily. The wiper blades then sweep once or twice after the WASH at low speed and then return to the previous wiper switch mode.

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

Push down on the wiper lever to activate a single wipe to clear off road mist or spray from a passing vehicle. As long as the lever is held down, the wipers will continue to operate.

Washer System
This vehicle is equipped with an electrically operated windshield washer pump. The washers are operated by a switch in the multi-function switch control lever. The lever is located on the right side of the steering column.

The electric pump assembly is mounted directly to the reservoir. A permanently lubricated motor is coupled to an impeller type pump. The pump and reservoir are serviced as separate assemblies.

To use the washer, pull the stalk lever toward you and hold while spray is desired. If the stalk lever is pulled while in the delay range, the wiper will operate for two wipe cycles (± 1) after the stalk lever is released, and then resume the intermittent interval previously selected.

The wash function can be accessed in the OFF position of the wiper control switch. Pulling the washer stalk lever rearward when the switch is in the OFF position will operate the wipers and washer motor pump continuously until the stalk lever is released. Releasing the stalk lever 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 stalk lever is pulled while in the OFF position, the wipers will operate for two wipe cycles, then turn OFF.

Fluid, gravity fed from the reservoir, is forced by the pump through rubber hoses to the hood mounted nozzles which direct the fluid streams to the windshield.

Wiper Blade - Typical:

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 and the passenger blade elements are 550 mm (21.65 in.) in length.