CONTINUOUS WIPE MODE
When the Low position of the control knob on the right (wiper) control stalk of the multi-function switch is selected,
the Body Control Module (BCM) energizes the wiper on/off relay. This directs battery current through the normally
open contacts of the energized wiper on/off relay and the normally closed contacts of the de-energized wiper high/
low relay to the low speed brush of the front wiper motor, causing the front wipers to cycle at low speed. When the
High position of the control knob is selected, the BCM energizes both the wiper on/off relay and the wiper high/low
relay. This directs battery current through the normally open contacts of the energized wiper on/off relay and the
normally open contacts of the energized wiper high/low relay to the high speed brush of the front wiper motor, caus-
ing the front wipers to cycle at high speed.
When the Off position of the control knob is selected, the BCM de-energizes both the wiper on/off and wiper high/
low relays, then one of two events will occur. The event that occurs depends upon the position of the wiper blades
on the windshield at the moment that the control knob 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 front wiper motor
is closed to ground 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 from the fused ignition switch output (run-acc) circuit of the front wiper motor.
The park switch directs this battery current to the low speed brush of the wiper motor through the wiper park switch
sense circuit and the normally closed contacts of the de-energized wiper on/off and wiper high/low relays. This
causes the wiper motor to continue running at low speed until the wiper blades are in the down position on the
windshield and the park switch is again closed to ground.
INTERMITTENT WIPE MODE
When the control knob on the right (wiper) control stalk of the multi-function switch is moved to one of the Delay
interval positions, the BCM electronic intermittent wipe logic circuit responds by calculating the correct length of time
between wiper sweeps based upon the selected delay interval input. The BCM monitors the changing state of the
wiper motor park switch through a hard wired front wiper park switch sense circuit input. This input allows the BCM
to determine the proper intervals at which to energize and de-energize the wiper on/off relay to operate the front
wiper motor intermittently for one low speed cycle at a time.
The BCM logic is also programmed to provide an immediate wipe cycle and begin a new delay interval timing cycle
each time a shorter delay interval is selected, and to add the remaining delay timing interval to the new delay inter-
val timing before the next wipe cycle occurs each time a longer delay interval is selected.
MIST WIPE MODE
When the right (wiper) control stalk of the multi-function switch is moved to the momentary Mist position, the BCM
energizes the wiper on/off relay for as long as the Mist switch is held closed, then de-energizes the relay when the
state of the Mist switch input changes to open. 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 Mist switch is held closed.
WASH MODE
When the right (wiper) control stalk of the multi-function switch is moved to the momentary front Wash position while
the control knob is in the Low or High positions, the circuitry within the switch directs battery current and ground to
the washer pump/motor unit. This will cause the washer pump/motor unit to be energized for as long as the front
Wash switch is held closed, and to de-energize when the front Wash switch is released.
When the right (wiper) control stalk of the multi-function switch is moved to the momentary front Wash position while
the control knob is in one of the Delay interval positions, the front washer pump/motor operation is the same. How-
ever, the BCM energizes the wiper on/off relay to override the selected delay interval and operate the front wiper
motor in a continuous low speed mode for as long as the front Wash switch is held closed, then de-energizes the
relay and reverts to the selected delay mode interval several wipe cycles after the front Wash switch is released.
The BCM detects the front Wash switch state through a hard wired washer pump driver circuit input from the multi-
function switch.
8R - 28
WIPERS/WASHERS - SERVICE INFORMATION
KJ