For 1990-2009 cars

### Wiper/Washer System Components

The Wiper/Washer System consists of the following components:

• | Windshield wiper/washer switch

• | Body control module (BCM)

• | Wiper On/OFF relay

• | Wiper HI/LO relay

• | Wiper diode

• | Windshield wiper motor

• | Windshield washer pump

• | WPR Fuse 10A

Refer to Wiper/Washer Component Views .

### Wiper/Washer System Operation

The windshield wiper motor is a 2 speed motor and is operated at low speed in all wiper modes except for high. Accessory voltage is supplied to the windshield wiper/washer switch from the WPR Fuse located in the BCM fuse block when the ignition is in the ACCESSORY or ON positions. The body control module (BCM) controls all wiper motor mist, wash, delay and low speed operations based on inputs received from the wiper/washer switch. The washer pump and high speed wiper operations are controlled directly by the wiper/washer switch.

### Low Speed Operation

When the wiper switch is in the LOW speed position, battery positive voltage is applied through the switch internal resistor and the wiper switch low/pulse signal circuit to the body control module (BCM). In response to this signal, the BCM energizes the wiper ON/OFF relay by applying battery voltage through the windshield wiper motor relay coil supply voltage circuit to the relay. This allows battery voltage from the WPR Fuse to flow through the switch side of the wiper ON/OFF relay and out to the switch side of the wiper HI/LO relay. Since the wiper HI/LO relay is de-energized and its switch contacts are normally closed to the low speed control circuit of the wiper motor, the motor will operate at low speed.

The wiper low speed operation and ON/OFF relay can also be commanded ON and OFF by using a scan tool. Refer to Scan Tool Output Controls .

### Mist Operation

Windshield wiper mist operation is identical to the wiper 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 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 5 resistors within the wiper/washer switch. The body control module (BCM) monitors the voltage on the wiper switch low/pulse signal circuit to determine the delay interval between the low speed wiper motor cycles.

If the wiper switch is moved from one delay interval to a another, the BCM will command an immediate wipe cycle and reset the delay timer.

### Wash Operation

When the windshield washer switch is pressed, battery voltage is applied through the switch contacts, the windshield washer pump control circuit and the body control module (BCM) to the windshield washer pump. The BCM monitors the voltage on the windshield washer pump control circuit to detect when a wash cycle is requested so it can also enable the wipers. After a short delay, the BCM energizes the wiper ON/OFF relay which will operate the windshield wiper motor at low speed. The wiper motor will continue to operate for 2 wipe cycles after the wash switch is released.

### High Speed Operation

In the wiper high speed position, the windshield wiper/washer switch supplies battery voltage to both the wiper ON/OFF relay and wiper HI/LO relay coils. This energizes both relays and allows battery voltage to flow through the wiper ON/OFF relay to the switched input of the wiper HI/LO relay through its switch contacts and out to the high speed control circuit of the wiper motor.

### Park Position Operation

Windshield wiper motor park operation is controlled by the body control module (BCM) using an input from the park switch 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. The signal circuit is pulled to ground by the wiper motor park switch when the wiper blades are in the down or 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 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.

The wipers will not park when they are commanded ON and OFF using a scan tool. The BCM will park the wipers the next time the wiper switch is turned ON and OFF.

### Windshield Wiper/Washer System Power and Ground

Battery positive voltage is supplied at all times to the wiper ON/OFF relay from the 10A WPR Fuse located in the BCM fuse block. Refer to Wiper/Washer Schematics .

G102 provides ground for the following components:

• | Windshield washer pump

• | Windshield wiper motor

• | Wiper HI/LO relay

• | Wiper ON/OFF relay