Automatic 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 rain sensor control module under the instrument panel, to the rain sensor within the base of the inside rear view mirror on the windshield, and to the multi-function switch. The internal circuitry of the multi-function switch provides direct hard wired battery current outputs to the rain sensor control module to indicate the selected wiper operating mode. The control module logic monitors the inputs from the multi-function switch as well as from the rain sensor and the wiper motor park switch in order to provide the outputs necessary to operate the wiper motor and the washer pump motor as requested.
When the automatic wipe position is selected with the multi-function switch control stalk, the rain sensor control module logic circuitry responds by providing an acknowledgment sweep of the wipers. The rain sensor calculates the correct wiper speed and wiper sweep intervals required to remove the moisture detected on the windshield glass and provides this input to the rain sensor control module. The control module then energizes and de-energizes the wiper motor automatically. The automatic wipe logic will also provide a wipe-after-wash feature to clear washer fluid that is directed onto the windshield when the washer system is utilized.
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, and the rain sensor control module logic circuit de-energizes the wiper motor. If the wiper blades are not in the down position at the moment the Off position is selected, the park switch is an open circuit. The control module logic circuit directs battery current to the low speed brush of the wiper motor, which 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 with the wiper system turned Off, the rain sensor control module logic circuitry operates the wiper motor in the same manner as it does to provide the automatic wipe mode operation. After the state of the washer switch changes to open the control module monitors the wiper motor through the wiper park switch sense circuit, which allows it to monitor the number of wiper blade sweeps. After the appropriate number of wiper sweeps the control module operates the wiper motor to return the wipers to their park position, then de-energizes the wiper motor.