GM Service Manual Online
For 1990-2009 cars only

Whenever the ignition switch is in the ON or the START position, battery voltage applies through the WIPER WASHER fuse to the front wiper/washer switch (in the combination switch) and to the front wiper motor pawl and switch contacts.

Washer Operation

When you pull the front wiper/washer switch back, battery voltage applies through the wash switch to the front washer pump. The front washer pump permanently grounds at G104 and operates as long as you hold the wash switch. In order to initiate wiper operation, turn the front wiper/washer switch to the LO or HI wiper positions.

Low Operation

With the front wiper/washer switch in the LO position, battery voltage applies through the WIPER WASHER fuse, and the LO contacts of the front wiper/washer switch to the low side of the front wiper motor. Since the front wiper motor permanently grounds at G109, the motor operates at low speed as long as the switch remains in the LO position. When you place the switch in the OFF position, the pawl and switch assembly provides voltage to the motor until the wipers are in the park position.

High Operation

With the front wiper/washer switch in the HI position, battery voltage applies through the WIPER WASHER fuse, and the high contacts of the front wiper/washer switch to the high side of the front wiper motor. Since the front wiper motor permanently grounds at G109, the motor operates at high speed as long as the switch remains in the HI position. When you place the switch in the OFF position, the pawl and switch assembly provides voltage to the motor until the wipers are in the park position.