Buick Regal: Description and Operation

WIPER/WASHER SYSTEM DESCRIPTION AND OPERATION

Wiper/Washer System Components

The wiper/washer system consists of the following electrical components:

• Windshield Wiper Relay
• Windshield Wiper Speed Control Relay
• Windshield Washer Pump
• Windshield Washer Pump Relay
• Windshield Wiper Motor
• Windshield Wiper/Washer Switch
• Body Control Module (BCM)
• Headlamp Washer Pump Relay (CE4)
• Headlamp Washer Pump (CE4)
• Rain Sensor
• Underhood Fuse Block (Contains Windshield Washer Pump PCB Relay)

Windshield Wiper System

The body control module (BCM) controls the wiper motor via two removable relays (Windshield Wiper Relay and Windshield Wiper Speed Control Relay). The BCM determines the wipe/wash system mode of operation by monitoring several signals from the Windshield Wiper/Washer Switch.

The BCM has 3 signal circuits, the first signal circuit is the Windshield Wiper Switch Low Reference, where the BCM provides a low reference signal to the Windshield Wiper/Washer Switch. Each input of the BCM provides a switched battery pull-up for each Windshield Wiper/Washer Switch output signal it receives.

The second signal circuit is the Windshield Wiper Switch Low Signal, and it consists of 6 resistors in the windshield wiper/washer switch configured as a resistor ladder network. The BCM monitors the voltage, and when high speed windshield wiper operation is requested, the windshield wiper control switch is connected to a different set of resistors into the circuit resulting in different voltages appearing on the BCM A/D input. To initiate low speed operation, the BCM only energizes the front wiper motor on/off relay. This allows battery voltage from the wiper fuse to be applied through the switched contacts of the wiper motor on/off relay, through the normally closed contacts of the wiper high/low speed relay, to the low speed control circuit of the windshield wiper motor.

The third signal circuit is the Windshield Wiper Switch High Signal, the BCM monitors the voltage, and when high speed windshield wiper operation is requested, the BCM continues to apply voltages to the windshield wiper relay control circuit and also applies ground to the windshield wiper speed control relay control circuit. This will cause the contacts in the windshield wiper speed control relay to close and apply B+ to the windshield wiper motor through the windshield wiper high speed control circuit, enabling high speed wiper operation.

Parking the wiper motor, the BCM monitors the park circuit until the park switch pulls the park circuit to ground. At this time, the BCM will immediately deactivate the wiper motor on/off relay. The relay contacts will switch back to their normally closed position and will apply ground to the wiper motor power inputs through the normally closed contacts of the wiper high/low relay. This deactivates and dynamically brakes the wiper motor in the park position.

When the wiper switch is turned to the OFF position while the wiper motor is somewhere in mid-cycle, the BCM will continue to operate the motor until the wipers reach the park position. If the BCM is running the wiper motor and does not see a state transition of the park switch after 8 s, the wipers will stop immediately when the wiper switch is turned to OFF. If the ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately, regardless of position. The BCM will park the wipers next time the ignition is turned ON.

The windshield wiper system MIST operation is identical to LOW speed operation, except that the MIST switch is a press and release type switch. When the wiper switch is moved to the MIST position and released, low speed wiper motor operation is started and will continue until 1 cycle is complete. If the wiper switch is moved to the MIST position and held, the wiper motor will operate in the LOW speed mode until the switch is released.

Windshield wiper intermittent operation is a low speed wiper motor function with a variable delay interval between the wiper motor cycles. The duration of the delay is controlled by the front wiper control switch's intermittent 1 thru intermittent 5 settings. The wiper operation is as follows.

1. The BCM will initiate a single wipe by activating its front wiper ON/OFF relay output.

2. At the completion of a single wipe, the BCM will park the wipers as described above.

3. The BCM will then pause the wipers in their park position for the time duration associated with intermittent delay switch setting.

4. When the delay time expires repeat Steps 1 and 3 until the system is turned off or taken out of intermittent mode. If the wiper switch is moved from a longer delay interval to a shorter delay interval, the BCM will command an immediate wipe cycle and reset the delay timer to the shorter delay interval.

Intermittent wiper operation may be vehicle speed sensitive. When enabled, the speed compensated intermittent feature causes the intermittent wiper delay intervals to become shorter as a function of increased speed. As vehicle speed is reduced the intervals will become closer to the predetermined.

S82 - S82 Windshield Wiper/Washer Switch
K9 - K9 Body Control Module
M75 - M75 Windshield Wiper Motor

Windshield Washer System

The windshield washer pump is controlled by the body control module (BCM) via a printed circuit board (PCB) relay. When the washer switch is depressed, the BCM monitors the Windshield Washer Switch signal circuit from the Windshield Wiper/Washer Switch. The BCM then applies voltage through a control circuit to the PCB windshield washer pump relay. With the relay energized, fused battery voltage is applied through the switch contacts of the relay and the control circuit to activate the windshield washer pump. To initiate wash operation, the Windshield Wiper/Washer switch should be pressed, causing the windshield washer to spray the washer fluid into the windshield, and the wiper automatically starts wiping.

S82 - S82 Windshield Wiper/Washer Switch
K9 - K9 Body Control Module
G24 - G24 Windshield Washer Pump

Headlamp Washer System

The headlamp washer pump is controlled by the body control module (BCM) via a removable relay. If the headlamp lights are on, the BCM will activate the headlamp washer pump the first time and the windshield washer pump is activated. After the initial headlamp washer activation, the BCM will only allow headlamp washer function every 5 windshield washer cycles. When the headlamp washer function is requested by the BCM's internal logic, it applies voltage through a control circuit to the headlamp washer pump relay. With the relay energized, fused battery voltage is applied through the switch contacts of the relay and the control circuit to activate the headlamp washer pump.

S82 - S82 Windshield Wiper/Washer Switch
K9 - K9 Body Control Module
G16 - G16 Headlamp Washer Pump

Washer Fluid Level Indicator

The check washer fluid message is controlled by the instrument cluster using signal from the Windshield Washer Fluid level Sensor. The washer fluid level signal circuit is supplied voltage through a resistor then monitored within the instrument cluster. The Windshield Washer Fluid level Sensor is normally close so the instrument cluster detects voltage on the Windshield Washer Fluid level Sensor signal circuit whenever the washer fluid level sensor is not low. When the washer fluid reaches the point where the driver should be informed that the washer fluid is low, the washer fluid level sensor opens. When the washer fluid level sensor is closed the washer fluid level signal circuit voltage is pulled low, and the instrument cluster displays the LOW WASHER FLUID INDICATOR message on the driver information center. In order to prevent the LOW WASHER FLUID INDICATOR message from being displayed while sloshing is occurring in the washer fluid container, the instrument cluster is programed with a 1 min delay before changing states of the check washer fluid message during an ignition cycle.

P16 - P16 Instrument Cluster
B118B - B118B Windshield Washer Fluid Level Switch

Rain Sense Mode and Rain Sense Indicator

The rain sensor communicates with the body control module (BCM) via serial data. When the ignition is in the ON or ACCESSORY position and the windshield wiper/washer switch is in the intermittent delay position, the BCM monitors the rain sensor data to determine the rain build up on the windshield. As rain builds up on the windshield, the BCM will command the wipers to activate. The sensitivity of the wiper frequency is controlled by the intermittent delay of the windshield wiper/washer switch. As the sensitivity is increased, the BCM will command more frequent wiper activation based on rain build up on the windshield.

K9 - K9 Body Control Module
B117 - B117 Rain Sensor

SPECIAL TOOLS AND EQUIPMENT

SPECIAL TOOLS

J 39822

Wiper Arm Puller

READ NEXT: