System Operation

Moving the column switch to the low or high speed position completes the respective brush circuit to 12V plus at the column switch and the wiper motor runs at that speed.

When the wiper is turned off at the column switch, in order to have the blades stop in their normal park position and the wiper motor shut off properly, the motor operates in low speed. This is accomplished as follows: with the column switch in the OFF position, the low speed brush circuit is completed to 12V plus at the column switch through a park switch located on the brush assembly (terminals 3 and 4). The park switch contacts are normally closed and this permits the wiper to continue to run.

When the blades reach their park position, a cam on the large gear moves the park switch actuator that opens the normally closed positive park switch and grounds the wiper motor. This accomplishes a reversal of the motor flux path which causes a no coast positive park, shutting off the wiper.