Jeep Liberty KJ. Manual - part 309

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.

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WIPERS/WASHERS - SERVICE INFORMATION

WIPE-AFTER-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 Off position, the BCM detects that switch state through a hard wired washer pump driver
circuit input from the multi-function switch. The BCM responds to this input by energizing the wiper on/off relay for
as long as the Wash switch is held closed, then de-energizes the relay several wipe cycles after the front Wash
switch is released. 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 count the number of wipe cycles that occur after
the front Wash switch state changes to open, and to determine the proper interval at which to de-energize the wiper
on/off relay to complete the wipe-after-wash mode cycle.

REAR

The rear wiper and washer system is designed to provide the vehicle operator with a convenient, safe, and reliable
means of maintaining visibility through the rear flip-up glass. The various components of this system are designed
to convert electrical energy produced by the vehicle electrical system into the mechanical action of the wiper blade
to wipe the outside surface of the glass, as well as into the hydraulic action of the washer system to apply washer
fluid stored in an on-board reservoir to the area of the glass to be wiped. When combined, these components pro-
vide the means to effectively maintain clear visibility for the vehicle operator by removing excess accumulations of
rain, snow, bugs, mud, or other minor debris from the rear flip-up glass surface that might be encountered while
driving the vehicle under numerous types of inclement operating conditions.

The vehicle operator initiates all rear wiper and washer system functions with the right (wiper) control stalk of the
multi-function switch that extends from the right side of the steering column, just below the steering wheel. Rotating
the control ring on the control stalk to a detent position selects the Off, Delay, or On rear wiper system operating
modes. Rotating the control ring on the control stalk to either of two Wash positions actuates the momentary rear
washer system switch. The multi-function switch provides hard wired outputs to the rear wiper module and the
washer pump/motor unit for all rear wiper and washer system functions.

The rear wiper and washer system will only operate when the ignition switch is in the Accessory or On positions,
and the rear flip-up glass and tailgate ajar switches are closed. Battery current is directed from a fuse in the Junc-
tion Block (JB) to the multi-function switch through a fused ignition switch output (run-accessory) circuit. The internal
circuitry of the right (wiper) control stalk of the multi-function switch then provides battery current signals through a
rear wiper on driver circuit and a rear wiper intermittent driver circuit to the rear wiper module and to the Body
Control Module (BCM). The BCM uses these rear wiper system inputs as a signal to lock the rear flip-up glass and
the tailgate to prevent the rear flip-up glass or tailgate from being opened for as long as the rear wiper is operating.
The multi-function switch circuitry also uses this battery current and a ground circuit input to directly control the
operation and direction of the reversible electric washer pump/motor unit.

A separate fuse in the JB provides battery current to the electronic control circuitry of the rear wiper module through
a fused B(+) circuit. The rear wiper module uses this fused B(+) input to park the rear wiper blade off of the rear
flip-up glass if the ignition switch is turned to the Off position while the rear wiper is operating, or if the ignition
switch is turned to the Off position before the rear wiper blade has parked. However, if the ignition switch is turned
to the Off position while the rear wiper is operating, then turned back On, the rear wiper switch must be cycled to
the Off position and back to the On or Delay position before the rear wiper will operate again. In addition, the rear
wiper module receives an input from the rear flip-up glass ajar switch on a flip-up glass ajar switch sense circuit,
which prevents the rear wiper from operating when the flip-up glass is not closed or fully latched.

The hard wired circuits and components of the rear wiper and washer system may be diagnosed and tested using
conventional diagnostic tools and procedures.

OPERATING MODES

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

CONTINUOUS WIPE MODE

When the On position of the control ring on the right (wiper) control stalk of the multi-function switch is selected, the
multi-function switch circuitry directs a battery current signal to the rear wiper module through the rear wiper on
driver circuit, causing the rear wiper to cycle continuously at a fixed speed.

WIPERS/WASHERS - SERVICE INFORMATION

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INTERMITTENT WIPE MODE

When the Delay position of the control ring on the right (wiper) control stalk of the multi-function switch is selected,
the multi-function switch circuitry directs a battery current signal to the rear wiper module through the rear wiper
intermittent driver circuit, causing the rear wiper to cycle intermittently at a fixed delay interval.

WASH MODE

When the momentary Wash (after On) position of the control ring on the right (wiper) control stalk of the multi-
function switch is selected, the multi-function switch circuitry directs both battery current and ground to the washer
pump/motor unit, and a battery current signal to be provided to the rear wiper module through the rear wiper on
driver circuit. This will cause the washer pump/motor unit to be energized and the rear wiper to cycle continuously
at a fixed speed for as long as the rear Wash switch is held closed.

WIPE-AFTER-WASH MODE

When the momentary Wash (before Off) position of the control ring on the right (wiper) control stalk of the multi-
function switch is selected, the multi-function switch circuitry directs both battery current and ground to the washer
pump/motor unit, and a battery current signal to be provided to the rear wiper module through the rear wiper on
driver circuit. This will cause the washer pump/motor unit to be energized and the rear wiper to cycle continuously
at a fixed speed for as long as the rear Wash switch is held closed. When the control ring is released to the Off
position, the washer pump/motor is de-energized, but the circuitry within the rear wiper module will provide several
additional wipe cycles to complete the wipe-after-wash mode cycle.

DIAGNOSIS AND TESTING

FRONT

WARNING: To avoid personal injury or death, on vehicles equipped with airbags, disable the supplemental
restraint system before attempting any steering wheel, steering column, airbag, occupant classification sys-
tem, seat belt tensioner, impact sensor, or instrument panel component diagnosis or service. Disconnect
and isolate the battery negative (ground) cable, then wait two minutes for the system capacitor to discharge
before performing further diagnosis or service. This is the only sure way to disable the supplemental
restraint system. Failure to take the proper precautions could result in accidental airbag deployment.

NOTE: If the front wiper motor operates, but the wipers do not move on the windshield, replace the inop-
erative front wiper module. If the washer pump/motor operates, but no washer fluid is dispensed on the
glass; or, if the wipers operate, but chatter, lift, or do not clear the glass, clean and inspect the front wiper
and washer system components as required. (Refer to 8 - ELECTRICAL/FRONT WIPERS/WASHERS -
CLEANING) and (Refer to 8 - ELECTRICAL/FRONT WIPERS/WASHERS - INSPECTION).

The hard wired front wiper and washer system circuits and components of the may be diagnosed and tested using
conventional diagnostic tools and procedures. Refer to the appropriate wiring information. The wiring information
includes wiring diagrams, proper wire and connector repair procedures, details of wire harness routing and retention,
connector pin-out information and location views for the various wire harness connectors, splices and grounds.

However, conventional diagnostic methods may not prove conclusive in the diagnosis of the Body Control Module
(BCM), or the inputs to or outputs from the BCM that provide front wiper and washer system service or many of the
electronic features of the front wiper and washer systems. The most reliable, efficient, and accurate means to diag-
nose the BCM, or the BCM inputs and outputs for the front wiper and washer system requires the use of a diag-
nostic scan tool. Refer to the appropriate diagnostic information.

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WIPERS/WASHERS - SERVICE INFORMATION

REAR

WIPER SYSTEM

NOTE: The diagnosis found here addresses an electrically inoperative rear wiper system. If the rear wiper
motor operates, but the wiper does not move on the rear flip-up glass, inspect the mechanical connection
between the rear wiper arm and the rear wiper motor output shaft. If OK, replace the inoperative rear wiper
module. If the wiper operates, but chatters, lifts, or does not clear the glass, clean and inspect the rear
wiper system components as required. (Refer to 8 - ELECTRICAL/REAR WIPERS/WASHERS - CLEANING)
and (Refer to 8 - ELECTRICAL/REAR WIPERS/WASHERS - INSPECTION).

1. Check that the interior lighting switch on the left (lighting) control stalk of the multi-function switch is not in the

dome lamp disable position. With all four doors and the tailgate closed, open the rear flip-up glass. The interior
lamps should light. Close the rear flip-up glass. Note whether the interior lamps remain lighted. They should turn
off after about thirty seconds. If OK, go to Step 2. If not OK, go to Step 9.

2. Check the fused B(+) fuse (Fuse 17 - 15 ampere) in the Junction Block (JB). If OK, go to Step 3. If not OK,

repair the shorted circuit or component as required and replace the inoperative fuse.

3. Check for battery voltage at the fused B(+) fuse (Fuse 17 - 15 ampere) in the JB. If OK, go to Step 4. If not OK,

repair the open fused B(+) circuit between the JB and the Power Distribution Center (PDC) as required.

4. Check the fused ignition switch output (run-acc) fuse (Fuse 22 - 10 ampere) in the JB. If OK, go to Step 5. If not

OK, repair the shorted circuit or component as required and replace the inoperative fuse.

5. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output (run-acc)

fuse (Fuse 22 - 10 ampere) in the JB. If OK, turn the ignition switch to the Off position and go to Step 6. If not
OK, repair the open fused ignition switch output (run-acc) circuit between the JB and the ignition switch as
required.

6. Disconnect and isolate the battery negative cable. Disconnect the instrument panel wire harness connector for

the multi-function switch (Connector C-2) from the switch connector receptacle. Reconnect the battery negative
cable. Turn the ignition switch to the On position. Check for battery voltage at the fused ignition switch output
(run-acc) circuit cavity of the instrument panel wire harness connector for the multi-function switch (Connector
C-2). If OK, go to Step 7. If not OK, repair the open fused ignition switch output (run-acc) circuit between the
multi-function switch and the JB as required.

7. Turn the ignition switch to the Off position. Disconnect and isolate the battery negative cable. Test the multi-

function switch. (Refer to 8 - ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/MULTI-FUNCTION SWITCH - DIAG-
NOSIS AND TESTING). If the multi-function switch tests OK, reconnect the instrument panel wire harness
connectors for the multi-function switch to the switch connector receptacles and go to Step 8. If the multi-function
switch does not test OK, replace the inoperative switch.

8. Remove the tailgate inner trim panel. Disconnect the tailgate wire harness connector for the rear wiper module

from the module connector receptacle. Check for continuity between the ground circuit cavity of the tailgate wire
harness connector for the rear wiper module and a good ground. There should be continuity. If OK, go to Step
9. If not OK, repair the open ground circuit to ground (G303) as required.

9. Check for continuity between the flip-up glass ajar switch sense circuit cavity of the tailgate wire harness con-

nector for the rear wiper module and a good ground. There should be continuity with the rear flip-up glass open,
and no continuity with the rear flip-up glass closed. If OK, go to Step 10. If not OK, repair the open flip-up glass
ajar circuit between the rear wiper module and the flip-up glass ajar switch as required.

10. Reconnect the battery negative cable. Check for battery voltage at the fused B(+) circuit cavity of the tailgate

wire harness connector for the rear wiper module. If OK, go to Step 11. If not OK, repair the open fused B(+)
circuit between the rear wiper module and the JB as required.

11. Turn the ignition switch to the On position. Turn the control ring on the right (wiper) control stalk of the multi-

function switch to the Delay position. Check for battery voltage at the rear wiper intermittent driver circuit cavity

WIPERS/WASHERS - SERVICE INFORMATION

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