Wiper and Washer Systems: Description and Operation

The pulse-type Windshield Wiper is operated by a two-speed Windshield Wiper Motor. The motor is controlled by the Wiper Switch on the Multi-Function Lever In the HIGH mode, the Windshield Wiper Motor operates at high speed without any delay after the end of a wipe cycle. When operated at any other speed, the motor operates at low speed. However, a variable delay time between wipe cycles is used to reduce the wipe frequency. The variable delay is determined by the Solid State Logic of the Windshield Wiper Motor and is based upon the input voltage on the BRN (96) wire from the Wiper Switch. The various resistors in the Wiper Switch divide the voltage seen by the Windshield Wiper Motor's fixed internal resistance. A higher switch resistance produces a lower input voltage at the motor. The Solid State Logic also contains logic which will return the wipers to the fully down position after the Windshield Washer Switch is placed in OFF.

The Windshield Washer Pump Motor is provided to spray the windshields as the wipers are moving. Each wiper has a flexible hose and nozzle which move with the wiper to apply spray where the wiper is in motion. The pump motor operated by the Windshield Wiper Motor in response to actuation of the momentary contact WASH lever switch on the Multi-Function Lever. When the WASH lever is actuated, the wiper motor operates the wipers at high speed and provides operating voltage to the washer pump motor on the RED (228) wire. As long as the WASH lever is held in place, the wipers and the Windshield Washer Pump Motor operate.

The Windshield Wiper Motor and the Windshield Washer/Wiper Switch are powered from WIPER Fuse 11 through the YEL (143) wire. The Windshield Wiper Motor and the Windshield Washer Pump Motor are grounded by the BLK (150) wire at Ground G201.

When the Windshield Washer/Wiper Switch is moved to the momentary contact MIST position, the low-speed voltage is placed on the BRN (96) wire to the Windshield Wiper Motor. This voltage is seen at the Variable Voltage Input of the Solid State Logic. The logic then produces voltage pulses at the Motor Output to the motor. The operating voltage is applied to the motor's low speed windings and the pulse duration is long enough for a complete wipe cycle. At low speed, there is no appreciable delay between pulses and the wipers operate almost continuously. These pulses are fed to the motor for the length of time that the MIST position is maintained by the driver. When the driver releases the switch, the Solid State Logic completes the current wipe cycle and then stops the wipers.

When the Wiper Switch is moved form the OFF position in the other direction , a momentary action Instant Wipe contact is closed as the switch moves towards the delay positions. This contact applies a momentary low-speed voltage to the wiper motor to start a wipe cycle. This avoids excessive delay in waiting for a delayed operation if a delay position is selected.

The remaining contacts on the Wiper Switch are maintained and do not require that the driver hold the switch in position. There are five delay positions labeled as "1" to "5" but represented by lines on the switch handle. In the first delay position, the highest resistance is selected by the switch. This produces the lowest voltage on the BRN (96) wire and the wiper motor operates with significant delay between wipes. Moving the switch to the other delay positions progressively selects decreased resistance in the switch and shorter delay times at the motor.

The next position is the LOW speed position. This position produces the low-speed voltage at the motor and the wipers operate at low speed without significant delay between wipes.

The last position is the HIGH position. In the HIGH position, the wiper switch closes contacts to apply full voltage on the PPL (92) wire to the motor. This voltage is applied to the motor's high speed winding. The HIGH position also closes contacts to apply the low-speed voltage to the motor on the BRN (96) wire. This voltage is used to allow the Solid State Logic to complete the wipe cycle when the switch is turned off. Without this, the wiper blades could stay in mid-wipe when the switch is turned off. The Solid State Logic also applies voltage to the motor's low speed winding but this has no effect as the high speed winding is operating.

The WASH lever of the Washer Switch is normally operated when the Wiper Switch is in the OFF position. This applies full battery voltage on the BRN (96) wire to the Windshield Wiper Motor. It also provides voltage on the PPL (92) wire through the diode shown in the center Wiper Switch contact set. This combination of voltages causes the wipers to operate at high speed and the Windshield Washer Pump Motor to operate. When the Washer Switch is released, the pump stops and the wipers complete the wipe cycles. Two or three wipe cycles follow the release of the Washer Switch and the stopping of the washer spray.