Principles of Operation
Operation of the windshield wiper and washer is controlled by the front wiper/washer amplifier assembly. The front wiper/washer amplifier input comes from the multifunction switch by means of a voltage divider circuit. A constant voltage is applied to the multifunction switch by the front wiper/washer amplifier. When the multifunction switch is moved into the LO, HI, or intermittent position, the voltage is directed through a series of resistors. This results in various voltages being returned to the module for each switch position. The module then grounds the appropriate circuit, based on the voltage signal received back from the multifunction switch. This causes the wipers to run intermittently, or at the appropriate speed. Voltage is supplied to the wiper motor by the CJB fuse F46 (20A).
When the multifunction switch wash button is depressed, it bypasses all of the resistors returning a full voltage signal to the module. The module then grounds the appropriate circuits to operate the windshield washer pump for as long as the switch is depressed. The windshield wiper speed is dependent on the position of the windshield wiper/washer switch.
Voltage for the windshield washer pump is also provided by CJB fuse F46 (20A).
Operation of the rear wiper and washer is controlled by the rear wiper/washer switch.
Voltage is supplied to the rear window wiper motor by the fuse junction panel fuse F44 (10A).
The rear window wiper motor ground is made or broken by the rear wiper/washer switch. When the rear wiper/washer switch is moved into the WIPER position, it grounds the rear window wiper motor circuit, causing the rear window wiper motor to run once every 10-15 seconds.
Voltage to the rear washer pump motor is also supplied by the CJB fuse F44 (10A). The rear washer pump is directly controlled by the rear wiper/washer switch which makes or breaks the ground for the washer pump motor, depending upon its position.
If the vehicle is equipped with a movable liftgate glass, a liftgate glass switch is utilized to prevent rear window wiper operation when the liftgate glass is open. This same switch also causes the rear window wiper to drop down approximately three inches when the liftgate glass latch is released.
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- The wipers stay on continuously — rear wiper
- Circuit.
- Rear wiper/washer switch.
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Measure the resistance between rear wiper/washer switch C288 pin 6, component side and rear wiper/washer switch C288 pin 2, component side.
- Is the resistance less than 5 ohms with the switch depressed, and greater than 10,000 ohms with it released?
Yes
GO to L2 .
No
INSTALL a new rear wiper/washer switch. TEST the system for normal operation.
Measure the resistance between rear wiper/washer switch C288 pin 6, circuit WB08 (BU/YE), harness side and ground.
- Is the resistance greater than 10,000 ohms?
Yes
INSTALL a new rear wiper /washer switch. TEST the system for normal operation.
No
REPAIR circuit WB08 (BU/YE). TEST the system for normal operation.
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