Intermittent Wipe System
When the ignition switch is in the On position, battery current from a fuse in the fuse block underneath the steering column is provided through a fused ignition switch output (run-start) circuit to the intermittent wipe logic circuitry of the wiper, turn signals and engine start control module within the fuse block, the multi-function switch, the wiper relay and the wiper motor park switch. The internal circuitry of the multi-function switch provides a direct hard wired battery current output to the low speed or high speed brushes of the wiper motor when the Low, High, or Pulse position is selected, which causes the wipers to cycle at the selected speed for as long as that switch position remains selected.
In order to provide the intermittent wipe and wipe-after-wash features, the intermittent wipe logic circuitry of the wiper, turn signals and engine start control module within the fuse block monitors inputs from the intermittent wipe and washer switch circuitry of the multi-function switch and the park switch in the wiper motor. When the intermittent wipe position is selected with the multi-function switch control stalk, the intermittent wipe logic circuitry responds by energizing the wiper relay and calculating the correct delay interval. The energized wiper relay directs battery current through the intermittent wipe position circuitry of the multi-function switch to the low speed brush of the wiper motor. The intermittent wipe logic circuit monitors the wiper motor operation through the wiper on/off relay output circuit, which allows it to determine the proper timing to begin the next wiper blade sweep. The normal delay interval is about five seconds.
When the Off position of the multi-function switch wiper control stalk is selected, one of two events is possible. The event that will occur depends upon the position of the wiper blades on the windshield at the moment that the Off position is selected. If the wiper blades are in the down position on the windshield when the Off position is selected, the park switch that is integral to the wiper motor is closed to ground, the intermittent wipe logic circuit de-energizes the wiper relay, and the wiper motor ceases to operate.
If the wiper blades are not in the down position on the windshield at the moment the Off position is selected, the park switch is closed to battery current through the fused ignition switch output (run-start) circuit. The intermittent wipe logic circuit energizes the wiper relay and the wiper on-off relay output circuit directs battery current to the low speed brush of the wiper motor through the normally open contact of the wiper relay, then through the internal Off position circuitry of the multi-function switch. This causes the wiper motor to continue running until the wiper blades are in the down position on the windshield and the park switch is again closed to ground.
When the Wash position of the control knob on the right control stalk of the multi-function switch is selected, the washer switch circuitry directs battery current to the washer pump motor and to the intermittent wipe logic circuitry. When the washer switch is closed with the wiper system turned Off, the intermittent wipe logic circuitry operates the wiper motor in the same manner as it does to provide the intermittent wipe mode operation. After the state of the washer switch changes to open, the intermittent wipe logic circuitry monitors the wiper motor through the wiper on-off relay output circuit, which allows it to monitor the number of wiper blade sweeps. After the appropriate number of wiper sweeps the intermittent wipe logic circuitry operates the wiper motor to return the wipers to their park position, then de-energizes the wiper relay.