Wiper and Washer Systems: Description and Operation

Description
The windshield wiper motor is a two speed, self parking unit driving two wiper arm wheel boxes via a flexible drive. A worm gear formed on the extended armature shaft drives a molded gear within the gearbox. The rotary motion of the motor being converted to a linear movement by a connecting rod actuated by a crankpin carried on the gear. The gearbox incorporates the self park mechanism which automatically parks the wiper blades at the end of the wiper cycle. Two speed operation is obtained by switching the positive feed to the third brush when the higher speed is selected.
With Off selected, the load relay is energized by selection of ``IGN ON'' and applies 12 volts through fuse No. 9 to terminal 1 on the wiper switch. 12 volts is internally fed through the wiper contact to terminal 7, and from there passes to terminal No. 1 on the wiper motor. This applies 12 volts to one side of the motor winding.
When Slow speed is selected, the 12 volts on terminal No. 1 of the switch is applied to terminal No. 5 and to terminal No. 5 of the wiper motor. A ground connection to terminal No. 2 on the switch is internally applied to terminal No. 7 and thereby to terminal No. 1 on the wiper motor. The motor then runs in a forward direction at slow speed.
When Fast speed is selected, the ground connection detailed above is maintained, but the 12 volt supply moved via terminal No. 4 on the switch and terminal No. 3 on the motor to the high speed brush. The motor then runs in a forward direction at a high speed.

Single Sweep Operation
A single sweep of the wiper is obtained by pulling the lever towards the steering wheel and releasing. When this position is selected and released, 12 volts are applied to both the coil of the timer unit, operating its contact, and to the terminal No. 1 on the motor. A ground is applied to the opposite brush of the motor, terminal No. 5 via the timer contact and an internal connection. The motor therefore starts and runs in a reverse direction. As the supply to the timer is applied then instantly removed, the contacts operate, then relax to the ``At Rest'' position. The motor ground on the brush of terminal No. 5 is achieved through the Park/Run contacts at the ``Run'' position, until the motor reaches the end of the sweep. The motor then stalls.

Intermittent Operation
When position ``D'' is selected, 12 volts are applied simultaneously to the operating coil of the timer and to terminal No. 1 of the wiper motor. Terminal No. 5 of the wiper motor is connected via terminal Nos. 5 and 6 of the switch to the timer contact.