GM Service Manual Online
For 1990-2009 cars only

Pulse Operation

With the wiper switch in DELAY (pulse), battery voltage is applied to the wiper motor connector at terminal B through CKT 143 and terminal G through CKT 477.

The length of the delay time between sweeps is controlled by the variable pulse delay resistor in the wiper/washer switch. The delay is adjustable from 1 to 22 seconds.

Rainsense Operation

With the wiper switch in AUTO DELAY (Rainsense), battery voltage is applied to the wiper motor connector at terminal B through CKT 143 and terminal G through CKT 477. Anytime the ignition switch is in RUN or ACCY, battery voltage is present at Rainsense module connector terminal 8 through CKT 43.

A pulse-width-modulated (PWM) signal is sent from the wiper motor cover to the Rainsense module through CKT 482. The type of PWM signal sent is determined by which AUTO DELAY position is selected on the wiper/washer switch.

The Rainsense module then sends a PWM signal back to the wiper motor cover on CKT 481. The type of PWM signal is determined by the input from the wiper motor cover and the amount of rain sensed on the windshield. The wiper motor cover receives the signal from the rainsense module and actuates the wiper motor accordingly.

Low Speed Operation

In the LO position of the wiper switch, battery voltage is applied to the wiper motor connector at terminal B through CKT 143 and terminal G through CKT 477.

High Speed Operation

In the HI position of the wiper switch, battery voltage is applied at terminals B, H and G of the wiper motor assembly through CKTs 143, 92 and 477.

Mist Operation

When the wiper switch is moved to MIST and released, the wipers make one sweep at low speed and return to park. The circuit operation is the same as that of low speed. If the wiper switch is held in MIST, the wipers will continue to operate until the switch is released. In the MIST position of the wiper switch, battery voltage is applied to the wiper motor connector at terminal B through CKT 143 and terminal G through CKT 477.

Washer Operation

When the washer switch is pushed, battery voltage is applied to terminal G of the wiper motor assembly through CKT 477. The wiper motor has voltage applied to it automatically by the wiper motor cover circuit board and operates at low speed during the wash cycle and then for two sweeps after the wash cycle is complete. If the wipers had been in DELAY, LO, or HI, they would return to that operation after the wash cycle.

CHECK WASHER FLUID (25)

The IPC receives a discrete input from the windshield washer solvent level switch. When the IPC receives a low signal from the windshield washer solvent level switch, the IPC displays the message.