Circuit/System Description
The Body Control Module (BCM) monitors the control circuit of the WIPER relay. The voltage level should be low while the WIPER relay is de-energized and near system voltage when the relay is energized. After the BCM receives a low, intermittent, or mist signal from the wiper/washer switch, it responds by applying battery voltage through the WIPER relay control circuit to the coil side of the relay, energizing the WIPER relay.
The Body Control Module (BCM) controls the washer pump motor based on an input from the windshield wiper/washer switch. The BCM monitors the washer switch through the windshield washer switch signal circuit. When the wash switch is closed, ground is supplied to the windshield washer switch signal circuit. When this is seen, the BCM will apply ground to the WSW relay control circuit and command the windshield washer fluid pump and the low speed wipers on.
The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation.
The body control module (BCM) controls the washer motor based on an input from the windshield washer switch, a part of the multifunction switch. The BCM monitors the washer switch through the windshield washer pump control circuit. When the WASH switch is closed, accessory voltage is supplied to the BCM which will command the windshield washer fluid pump and the low speed wipers On.
The body control module (BCM) controls the wiper motor based on input from the windshield wiper washer switch. The BCM monitors the wiper washer switch through three separate signal circuits and a ground circuit. The windshield wiper switch high signal circuit is used to determine high speed wiper operation, the windshield wiper switch low signal is used to determine low speed, intermittent, and mist operation through the use of a resistor ladder, and windshield washer switch signal circuit is used to determine washer operation.
The BCM controls the windshield wiper motor through two output controls, controlling two relays which determine the desired wiper speed, high or low.
The instrument panel cluster (IPC) monitors the washer fluid level sensor via the washer fluid level sensor signal circuit. With the switch closed, the signal circuit is pulled to ground indicating low fluid level. When low fluid level is indicated, the IPC will illuminate the low washer fluid indicator.
The rear wiper is controlled based on an input from the rear wiper/washer switch. When closed, the wiper ON switch provides a voltage signal to the rear window wiper motor indicating rear wiper operation is requested. The rear wiper motor receives B+ voltage from the I/P fuse block and accessory voltage from the body control module (BCM).
The rear washer is activated based on an input from the rear washer switch. When the wiper portion of the rear wiper/washer switch is closed, B+ is applied to the REAR/WSW relay indicating rear washer operation is requested. With B+ applied to the relay coil, the relay is energized and B+ is supplied to the washer pump.
Rear Wiper Operation
The rear wiper is controlled by an input from the rear wiper/washer switch which is located in the center console switch bank. The rear wiper/washer switch is a three position switch, when the WIPER portion of the switch is pushed into it's detent the rear wipers are turned on, a voltage signal from the BCM is applied through the wiper washer switch to the rear wiper motor to command it ON. With the switch in the center or rest position the wipers are OFF.
Rear Washer Operation
When the WASHER portion of the switch is pressed the rear washers are turned on, the switch has a momentary contact in the washer position and will continue to spray as long as the switch is being pressed and will stop when it is released. When the wiper portion of the rear wiper/washer switch is closed, B+ is applied to the REAR/WSW relay indicating rear washer operation is requested. With B+ applied to the relay coil, the relay is energized and B+ is supplied to the washer pump.
Modes of Operation
The normal wiper system function positions are as follows
- MIST
- DELAY
- MANUAL LOW
- MANUAL HIGH
- WASH
Automatic Modes of Operation
- AUTOMATIC DELAY
- AUTOMATIC LOW
- AUTOMATIC HIGH
Automatic low speed and automatic high speed wiper modes are continuous wiper operations that are controlled by the outside moisture sensor. Automatic low and high speed operation is utilized when the amount of precipitation on the windshield exceeds the automatic delay or low threshold.
Low Speed Operation
When the wiper switch is in the low speed position, ground is applied through a resistor internal to the switch and the wiper switch low signal circuit to the body control module (BCM). In response to this signal, the BCM energizes the WPR relay by applying battery voltage through the wiper relay control circuit to the coil side of the relay. This allows battery positive voltage from the WPR fuse to flow through the switch input side of the WPR relay and out to the switch input side of the WPR HI relay. Since the wiper high relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the windshield wiper motor, the motor will operate at low speed.
Wiper motor low speed operation and the WPR relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References .
Mist Operation
Windshield wiper/washer system MIST operation is identical to wiper Low 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 wipe cycle is complete. If the wiper switch is moved to the mist position and held, the wiper motor will operate in the low mode until the switch is released.
Delay Operation
Windshield wiper delay operation is a low speed wiper motor function with a variable delay interval between the wiper motor cycles. The delay interval is determined by a series of 6 resistors within the wiper/washer switch. The body control module (BCM) monitors the wiper switch low signal circuit to determine the delay interval between the low speed wiper motor wipe cycles.
High Speed Operation
When the wiper switch is in the high speed position, ground is applied through the windshield wiper switch high signal circuit to the body control module (BCM) indicating the wiper high speed request. In response to this signal, the BCM then energizes the WPR relay, as stated above, and the WPR HI relay by applying ground through the control circuit to the coil side of the relay. With the wiper high relay energized and its switch contacts closed to the high speed control circuit of the wiper motor, the motor will operate at high speed.
The wiper high speed relay can also be commanded ON/OFF by using a scan tool. However, before commanding the wiper motor high speed mode ON/OFF using a scan tool, the WPR relay must be energized by placing the wiper switch in the low speed position. Refer to Control Module References .
Wash Operation
When the windshield Wash switch is pressed, ground is applied through the switch contacts and the windshield washer switch signal circuit to the body control module (BCM) indicating the windshield wash request. The BCM then energizes the WPR relay, as stated above, and the WSH relay by applying ground through the control circuit to the coil side of the relay. With the wash relay energized, battery voltage from the WPR fuse is applied through the switch side of the relay and out to the control circuit of the windshield washer fluid pump. The wiper motor will operate for 2 wipe cycles after the wash switch is released.
The WSH relay can also be commanded ON/OFF by using a scan tool. Refer to Control Module References .
Park Position Operation
Windshield wiper motor park operation is controlled by the body control module (BCM) using an input from the park switch that is located within the wiper motor assembly. The BCM monitors the windshield wiper motor park switch signal circuit, to determine if the windshield wiper blades are at the bottom of the glass. During wiper operation, each time the wiper blades are at the bottom of the glass, the park switch is momentarily closed to ground signaling the BCM the wiper 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 ignition is turned OFF while the wipers are in mid-cycle, the wipers will stop immediately where they are. The BCM will park the wipers the next time the ignition is turned ON.