In addition to the features of a conventional (non-pusle) wiper system (mist, low and high speeds), the pulse type windshield wiper/washer system includes an operating mode in which the wipers make single sweeps with an adjustable time interval between sweeps. The time interval is controlled by a solid state timer in the wiper motor cover assembly. The duration of the delay interval is determined by the delay resistor in the wiper/washer switch assembly.

When the wiper switch is turned OFF, the wiper motor returns the wipers to end of the sweep (inner wipe) position, the wiper motor reverses and activates its external depressed park mechanism to lower the wipers to the park position.

When the wiper switch is moved to the HI position, battery voltage is applied to the wiper motor connector at terminals B, C, and E through CKTs 143, 92 and 95. Voltage is also applied to terminal D through CKT 91.

The circuit board supplies power to the wiper motor, which runs continuously at high speed.

When the wiper switch is moved to the LO position, battery voltage is applied to the wiper motor connector at terminals B, E through CKTs 143, 95. Voltage is also applied to terminal D through CKT 91.

The circuit board supplies power to the wiper motor, which runs continuously at low speed.

When the wiper switch is moved to the INT position, battery voltage is applied the wiper motor connector at terminals B and E through CKTs 143 and 95. Voltage is also applied at terminal D through CKT 91.

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

When the wiper switch is moved to the OFF position from the HI, LO, or INT operating positions, the wipers complete the last sweep and park. When the wiper switch is in the OFF position, the wiper motor assembly has battery voltage applied to terminal B only, from CKT 143. When the end of sweep switch opens, the control circuit reverses the wiper motor which activates the external depressed park mechanism. The wiper motor continues to run until the park switch opens.

When the wiper switch is moved to the MIST position and released, the wipers make one sweep at low speed and return to the park position.

When the windshield washer switch is pushed (closed), current flows through the park switch coil to ground closing the park switch contacts. Current flows through the park switch contacts and wiper motor to ground. The wiper motor operates at low speed. Current also flows through the circuit board and the park switch coil to ground keeping the park switch contacts closed after the washer switch is released. The circuit board allows current to flow through the washer pump for 2-1/2 seconds after the washer switch is released, or for as long as the washer switch is held closed. The circuit board interrupts power to the park switch coil approximately six seconds after the washer switch is released. This turns off the wiper motor and the wiper arms to return to the park position.

Before performing wiper system diagnosis, make the following checks.

If the washer does not operate, check that: