For 1990-2009 cars

The windshield wiper/washer system consists of front and rear wipers. The front and rear wipers are operative when the vehicle is in accessory or run. The front wipers have 4 different modes: Mist, Intermittent, Low, and High. When the front wipers are in the intermittent mode, there are 5 delay modes to chose from, commanded by the windshield wiper washer switch through the body control module (BCM). The rear wipers has an only one mode.

### Rear Wiper Operation

During rear wiper operation, the wiper switch portion of the rear wiper/washer switch provides a ground signal to the rear wiper motor indicating the rear wipers are requested. At this point the rear will motor will activate. The wiper motor is supplied B+ through the I/P fuse block and accessory voltage from the BCM.

Rear wiper operation will be suspended when the liftgate is open. The rear wiper motor monitors the liftgate ajar switch to determine when the liftgate is open.

### Low and Intermittent Operation (Front Wipers)

During Low and Intermittent operation, the windshield wiper washer switch provides a resistor ladder to determine the amount of wiper delay requested. The wiper delay is determined by the BCM based on the input from the wiper washer switch. In the Low and Intermittent position, the windshield wiper washer switch supplies a ground signal to the windshield wiper switch low signal circuit indicating to the BCM that intermittent or low speed wiper operation is request. The resistor ladder determines the voltage signal seen at the BCM, with various voltage levels equaling different delay speeds. Upon this signal, the BCM will apply B+ to the WIPER PCB relay coil. The relay coil will become energized, creating a magnetic field and closing the relay switch. B+ will be applied to the windshield wiper motor low control circuit. During low speed operation, the BCM will supply B+ to relay continuously, operating the wipers at a steady low speed. During intermittent operation, the BCM will selectively supply B+, providing the intermittent delay.

### High Operation (Front Wipers)

In the High position, the windshield wiper washer switch supplies a ground signal to the windshield wiper switch high signal circuit indicating to the BCM that high speed wipers are requested. Upon this signal, the BCM will ground the WIPER HIGH PCB relay coil via the Front Windshield Wiper High Signal Control circuit. The relay coil will become energized, creating a magnetic field and closing the relay switch. B+ will be applied to the windshield wiper motor high control circuit.

### Mist Operation (Front Wipers Only)

In the Mist position, the windshield wipers make one sweep at low speed and returns to the park position and functions in the same manner as the low speed operation. If the windshield wiper washer switch is held in Mist position, the windshield wipers will continue to operate until the switch is released.

### Park Position Operation

When the wipers are commanded on, B+ is supplied to the windshield wiper motor park switch signal. With B+ applied, the wipers will park when in the at rest state.

### Wash Operation (Front and Rear Wipers)

The front and rear washer systems use a common windshield washer fluid pump. When either the front or rear wiper is in the washer position voltage will be supplied to one side of the windshield washer fluid pump (depending on whether front or rear washer has been requested), while the other side of the pump is grounded.

During front washer requests, the windshield wiper washer switch supplies a ground signal to the windshield washer switch signal circuit indicating to the BCM that washers are requested. Upon this signal, the BCM will ground the WIPER PCB relay coil and the FRT WASHER PCB relay. This will operate the wipers at a low speed and activate the washer pump for as long as the Wash switch is held.

During front washer requests, the washer portion of the rear wiper/washer switch provides ground to the RR WASH PCB relay and also supplies a signal to the rear wiper motor indicating washer and wiper events are requested.