Wiper and Washer Systems: Description and Operation

With the Ignition Switch in ACC or RUN, voltage is available to the Wipers and Washers through the WIPER Fuse and the WHT (93) wire.

When the Wiper/Washer Switch is in LO, battery voltage is supplied through the GRA (91) wire directly to the low speed brushes of the Wiper Motor. The Wiper Motor runs at low speed.

When the Wiper/Washer Switch is in Hi, battery voltage is supplied through the PPL (92) wire to the high speed brushes of the Wiper Motor. The Wiper Motor operates at high speed.

The Park Switch is open only when the wiper blades are in the Park position. in all other positions, the Park Switch is closed. When the Wiper/Washer Switch is moved to OFF, battery voltage at the WHT (93) wire is supplied through the Park Switch, the ORN (98) wire, the Wiper/Washer Switch, and the GRA (91) wire to the low speed brushes of the Wiper Motor. The Wiper Motor continues to run at low speed until the wiper blades reach the Park position. At that time, the Park Switch opens and stops the Wiper Motor.

The Wiper Motor is protected by a circuit breaker which opens if the current through the Motor rises to a high level. This may happen if the wiper blades are blocked by ice or snow. The circuit breaker resets automatically after it cools off.

WIPER (PULSE)

In addition to the features of a conventional (non-pulse) Wiper System (MIST, LO, and HI speeds), the Pulse Wiper/Washer system includes an operating mode in which the Wipers make single strokes with an adjustable time interval between strokes. The time interval is controlled by a Solid-State Delay/Speed/Wash Control in the Wiper Motor Module. The duration of the time interval is determined by the Pulse Resistance Rheostat in the Wiper/Washer Switch.

LOW SPEED

In the LO position, the Wiper/Washer Switch supplies voltage to the GRA (91) wire and the Delay/Speed/Wash Control. The Delay/Speed/Wash Control provides ground to the Park/Run Relay which is energized and supplies voltage to the brushes of the Wiper Motor. The Wipers run at low speed until they are turned off.

HIGH SPEED

With the Wiper/Washer Switch in the HI position, battery voltage is supplied from the PPL (92) wire directly to a second armature terminal of the Wiper Motor. The wipers run at high speed. When the Wiper/Washer Switch is turned to OFF, the Wipers complete the last sweep at low speed and park.

PARK

When the Wipers are turned off, the Wiper Motor runs at low speed until the wiper blades reach the PARK position. At that time the Park/Run Relay opens, stopping the Wiper Motor immediately. The wiper blades remain in the PARK position.

MIST

When the control 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 low speed.

PULSE

With the Wiper/Washer Switch in PULSE, voltage is applied to the GRA (91) wire, the Wiper Motor Module, and the Solid-State Control Board. Voltage is supplied to the Park/Run Relay coil which is momentarily grounded by the Delay/Speed/Wash Control circuit and the relay closes. Battery voltage is supplied by the WHT (93) wire through the closed contacts of the Relay to run the Wiper Motor in LO speed. The Relay remains energized as long as the contacts of the Park/Run Switch remain closed. When the wiper blades have reached PARK the Park/Run Switch opens, deenergizing the Park/Run Relay. The wiper blades remain in PARK until the Control Board grounds the Park/Run Relay coil to start another sweep. The delay time between sweeps is controlled by the delay resistors. The delay can be adjusted from 0 to 43 seconds.

WASHER (CONVENTIONAL WIPER)

The Washer Motor is energized whenever the Washer Switch is pressed and runs as long as the Washer Switch is closed. Battery voltage is supplied through the Washer Switch and the PNK (94) wire to the Washer Motor. The other terminal of the Motor is grounded through the BLK (150) wire.

WASHER (PULSE WIPER)

When the Washer Switch is depressed, voltage is supplied to the Solid-State Control Board in the Wiper Motor Module. The Control Board supplies battery voltage to the Washer Motor through the ORN (98) wire, Wiper Switch and PNK (94) wire. It also starts the wiper cycle through the low speed brushes of the Wiper Motor. The Washer continues to run as long as the switch is held down. The Solid-State Control Board keeps the Wipers on for approximately six seconds after the Washer goes off. If the Washer is switched ON during the DELAY operation, the Wipers run in low speed for six seconds. When the wash cycle is completed, the Wipers return to the pulse operation.