GM Service Manual Online
For 1990-2009 cars only

Pulse Operation

With the wiper switch in the DELAY (pulse) position, battery voltage is applied to the wiper motor connector at terminal B through CKT 143. Voltage is also applied to terminal D through CKT 113 and terminal E through CKT 112.

The length of delay time between sweeps is controlled by the variable-pulse delay resistor. Delay is adjustable from 1-22 seconds, nominally.

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, terminal E through CKT 112, and terminal D through CKT 113.

High-Speed Operation

In the HI position of the wiper switch, battery voltage is applied at terminals B, C, and E of the wiper motor assembly through CKTs 143, 92, and 112. Voltage is also applied to terminal D through CKT 113.

Park Position Operation

When turned OFF from any position, the wipers complete the last sweep and park. When the wiper switch is in OFF, the wiper motor assembly has battery voltage applied to terminal B only, from CKT 143.

Washer Operation

When the washer switch is turned to ON, battery voltage is applied to terminal D of the wiper motor assembly through CKT 113. The washer switch also applies voltage to the washer pump through CKT 228. The wiper motor operates at low speed for 3-5 wipes.

If the wipers had been in DELAY, LO, or HI, they would return to that operation after the wash cycle. If they had been in the OFF position, they would then return to the park position after 3-5 wipes.

Mist Operation

When the wiper switch is moved to MIST and released, the wipers make one sweep at low speed and return to the park position. If the wiper switch is held in MIST, the wipers will continue to operate until the switch is released. The circuit operation is the same as that of low speed.