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

Power to the windshield wiper/washer system is supplied from the following sources:

Ground to the windshield wiper/washer system is supplied from the following ground points:

The winsdhield wiper/washer system is controlled by the Body Control Module (BCM). The BCM receives inputs from the windshield wiper/washer switch, the rain senor (if fitted), park switch (in the wiper motor) and vehicle speed data from the HS GMLAN network. The BCM processes the input information and activates the appropriate relays located in the Underhood Body Electric Centre to control the windshield wiper and washer motors.

The winshield wiper mist switch is a momentary switch which returns to the off position when released. The windshield wiper will perform one wipe cycle when the mist switch is activated and released. If the mist switch is held in the on position the windshield wiper will activate until the switch is released. When the wiper switch is in the mist position terminal X1-9 in the BCM is grounded through a 332 ohm resistor in the windsield wiper switch. The BCM monitors the voltage at terminal X1-9 and upon detecting a voltage change activates the low speed relay for as long as the wiper switch is held in the on position. When the switch is released the low speed relay is deactivated by the BCM and it returns to the its rest position dynamically breaking the wiper motor to its park position.

In the intermittent position the windshield wiper will perform one wipe cycle, wait a delay period and repeat this action until a different wiper switch function is selected. Rotating the INT collar on the wiper switch through its five positions, will increase or decrease the delay period between windshield wipe cycles. The delay period between wipe cycles is also decreased automatically as the vehicle speed increases. When the intermittent positon is selected terminal X1-9 at the BCM is grounded through a series of resistors in the wiper switch. The BCM monitors the voltage at terminal X1-9 and upon detecting the voltage change, activates the low speed relay. Power is then supplied by the low speed relay through the high speed relay rest contacts to terminal 4 of the windshield wiper motor.

The intermittent switch resistance values are:

In the auto position the electrical functionality of the wiper switch is identical to the intermittent position except the INT collar controls the sensitivity of the rain sensor. The rain sensor communicates to the BCM via two circuits using a PWM. The BCM transmits data to the rain sensor on what setting the INT collar is set to and the rain sensor commands the BCM to operate the wipers. Depending on the frequency of the rain the BCM can operate the wipers on intermittent, low or high speed modes.

When the low speed position is selected terminal X1-9 at the BCM is grounded through a 331 ohm resistor in the wiper switch. Terminal X1-5 is also grounded in the wiper switch. The BCM monitors the voltage at terminal X1-9 and upon detecting the voltage change, activates the low speed relay. Power is then supplied by the low speed relay, through the high speed relay rest contacts to terminal 4 of the windshield wiper motor

When the high speed position is selected terminal X1-9 at the BCM is grounded through a 331 ohm resistor in the wiper switch. The BCM monitors the voltage at terminal X1-9 and X1-5 and upon detecting the voltage change, activates the low and high speed relays. Power is then supplied by the low speed relay, through the high speed relay ON contacts to terminal 3 of the windshield wiper motor.

When the wash position is selected terminal X1-24 at the BCM is grounded through the wiper switch. The BCM monitors the voltage at terminal X!--24 and upon detecting the voltage change, activates the washer pump relay. Power is then supplied from the washer pump relay through fuse F21 to terminal 1 on the washer pump motor. When the windshield washer has been activated the BCM will also activates the low speed windshield wiper which will carry out 3 to 5 wipe cycles.