Operating Modes

WARNING: This page is about a different car, the 2014 Fiat 500e. However, it is still accessible from the selected car via links, so may be relevant.

Following are paragraphs that briefly describe the operation of each of the front wiper and washer system operating modes.

Continuous Wipe Mode - When the Low position of the right (wiper) multifunction switch control stalk is selected, the switch provides a resistor multiplexed input to the BCM. The BCM responds by energizing a relay that directs battery current to the low speed brush of the wiper motor, causing the wipers to cycle at low speed.
When the High position of the right (wiper) multifunction switch control stalk is selected, the switch provides a resistor multiplexed input to the BCM. The BCM responds by energizing a relay that directs battery current to the high speed brush of the wiper motor, causing the wipers to cycle at high speed.

When the Off position of the right multifunction switch control stalk is selected, the switch provides a resistor multiplexed input to the BCM. The event that occurs depends upon the position of the wiper blades on the windshield at the moment that the control stalk 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, which provides a hard wired park switch sense input to the BCM. The BCM then de-energizes the wiper motor 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 an open circuit and the BCM continues running the wiper motor at low speed until the wiper blades are in the down position on the windshield and the park switch input to the BCM is again closed to ground.
Intermittent Wipe Mode - When the right (wiper) multifunction switch control stalk is moved to the Delay (or Intermittent) position, the switch provides a resistor multiplexed input to the BCM. The BCM electronic intermittent wipe logic circuit responds by calculating the correct length of time between wiper sweeps based upon both time and electronic vehicle speed message inputs. The BCM then provides control outputs to energize and de-energize the relays to operate the wiper motor intermittently for one low speed cycle at a time.
Mist Wipe Mode - When the right (wiper) multifunction switch control stalk is moved downward to the momentary Mist (or Pulse) position, the switch provides a resistor multiplexed input to the BCM. The BCM responds by energizing a relay that directs battery current to the low speed brush of the wiper motor, causing the wipers to operate for one complete low speed cycle. The BCM can operate the front wiper motor in this mode for only one low speed cycle at a time, or for an indefinite number of sequential low speed cycles, depending upon how long the switch is held closed.
Wash Mode - When the control stalk of the right (wiper) multifunction switch is pulled rearward to the momentary Front Wash position, the switch provides a resistor multiplexed input to the BCM. The BCM responds by providing battery current and ground to the washer pump/motor. This will cause the washer pump/motor to be energized in the front wash direction for as long as the switch is held closed and to be de-energized when the control stalk is released.
When the control stalk is pulled rearward to the momentary Front Wash position while the front wiper system is operating in the Delay mode, the washer pump/motor operation is the same. However, the BCM also overrides the Delay mode and operates the front wiper motor in a continuous low speed mode for as long as the control stalk is held in the Wash position, then reverts back to the Delay mode several wipe cycles after the control stalk is released.
Wipe-After-Wash Mode - When the control stalk of the right (wiper) multifunction switch is pulled rearward to the momentary Front Wash position for more than about one-half second while the wiper system is not operating, the BCM directs battery current and ground to the washer pump/motor and energizes the wiper motor in a continuous low speed mode for as long as the switch is held closed. When the control stalk is released, the BCM de-energizes the washer pump/motor immediately, but allows the wiper motor to operate for several additional wipe cycles before it de-energizes the wiper motor and parks the wiper blades near the base of the windshield.
The BCM monitors the changing state of the wiper motor park switch through a hard wired wiper park switch sense circuit input. This input allows the BCM to monitor the number of wipe cycles that occur after the control stalk is released, and to determine the proper interval at which to de-energize the wiper motor to complete the Wipe-After-Wash mode cycle.