2002 JEEP LIBERTY Bcm wiring

An electrically operated intermittent front wiper
and washer system is standard factory-installed
safety equipment on this model (Fig. 1). The front
wiper and washer system includes the following
major components, which are described in further
detail elsewhere in this service information:
²Body Control Module- The Body Control
Module (BCM) is located on the Junction Block (JB)
under the driver side outboard end of the instrument
panel. (Refer to 8 - ELECTRICAL/ELECTRONIC
CONTROL MODULES/BODY CONTROL MODULE
- DESCRIPTION).
²Front Check Valve- The front washer system
check valve is integral to the wye fitting located in
the washer plumbing between the cowl plenum
washer hose and the front washer nozzles, and is
concealed beneath the cowl plenum cover/grille panel
at the base of the windshield.
²Front Washer Nozzle- Two fluidic front
washer nozzles are secured with integral snap fea-
tures to dedicated openings in the cowl plenum cover/
grille panel located near the base of the windshield.
²Front Washer Plumbing- The plumbing for
the front washer system consists of rubber hoses and
molded plastic fittings. The plumbing is routed along
the right side of the engine compartment from the
washer reservoir, and through the dash panel into
the cowl plenum to the front washer nozzle fittings
beneath the cowl plenum cover/grille panel.
²Front Wiper Arm- The two front wiper arms
are secured with nuts to the threaded studs on the
ends of the two wiper pivot shafts, which extend
through the cowl plenum cover/grille panel located
near the base of the windshield.
²Front Wiper Blade- The two front wiper
blades are secured to the two front wiper arms with
an integral latch, and are parked on the glass near
the bottom of the windshield when the front wiper
system is not in operation.
²Front Wiper Module- The front wiper pivot
shafts are the only visible components of the front
wiper module. The remainder of the module is con-
cealed within the cowl plenum area beneath the cowl
plenum cover/grille panel. The front wiper module
includes the wiper module bracket, four rubber-iso-
lated wiper module mounts, the front wiper motor,
the wiper motor crank arm, the two wiper drive
links, and the two front wiper pivots.
²Multi-Function Switch- The multi-function
switch is located on the top of the steering column,
just below the steering wheel. The multi-function
switch includes a left (lighting) control stalk and a
right (wiper) control stalk. The right control stalk is
dedicated to providing all of the driver controls for
both the front and rear wiper systems. (Refer to 8 -ELECTRICAL/LAMPS/LIGHTING - EXTERIOR/
MULTI-FUNCTION SWITCH - DESCRIPTION).
²Washer Fluid Level Switch- The washer fluid
level switch is located in a dedicated hole near the
center of the rearward facing surface of the washer
reservoir, behind the right front wheel house splash
shield.
²Washer Pump/Motor- The reversible electric
washer pump/motor unit is located in a dedicated
hole on the lower outboard side of the washer reser-
voir, behind the right front wheel house splash
shield. This single reversible washer pump/motor
provides washer fluid to either the front or rear
washer system plumbing, depending upon the direc-
tion of the pump motor rotation.
²Washer Reservoir- The washer reservoir is
concealed behind the right front wheel house splash
shield ahead of the right front wheel. The washer
reservoir filler neck is the only visible portion of the
reservoir, and it is accessed from the right front cor-
ner of the engine compartment.
²Wiper High-Low Relay- The wiper high-low
relay is an International Standards Organization
(ISO) micro relay located in the Power Distribution
Center (PDC) in the engine compartment near the
battery.
²Wiper On-Off Relay- The wiper on-off relay is
an International Standards Organization (ISO) micro
relay located in the Power Distribution Center (PDC)
in the engine compartment near the battery.
Hard wired circuitry connects the front wiper and
washer system components to the electrical system of
the vehicle. These hard wired circuits are integral to
several wire harnesses, which are routed throughout
the vehicle and retained by many different methods.
These circuits may be connected to each other, to the
vehicle electrical system and to the front wiper and
washer system components through the use of a com-
bination of soldered splices, splice block connectors,
and many different types of wire harness terminal
connectors and insulators. Refer to the appropriate
wiring information. The wiring information includes
wiring diagrams, proper wire and connector repair
procedures, further details on wire harness routing
and retention, as well as pin-out and location views
for the various wire harness connectors, splices and
grounds.
OPERATING MODES The components of the front
wiper and washer system are designed to work in
concert to provide the following operating modes:
²Continuous Wipe Mode- The control knob on
the right (wiper) control stalk of the multi-function
switch has two continuous wipe positions, Low and
High. When selected, these switch positions will
cause the two-speed front wiper motor to operate in a
continuous low or high speed cycle.
KJFRONT WIPERS/WASHERS 8R - 3
FRONT WIPERS/WASHERS (Continued)

cycles that occur after the front Wash switch state
changes to open, and to determine the proper inter-
val at which to de-energize the wiper on/off relay to
complete the wipe-after-wash mode cycle.
DIAGNOSIS AND TESTING - FRONT WIPER &
WASHER SYSTEM
FRONT WIPER SYSTEM
If the front wiper motor operates, but the wipers
do not move on the windshield, replace the faulty
front wiper module. If the wipers operate, but chat-
ter, lift, or do not clear the glass, clean and inspect
the front wiper system components as required.
(Refer to 8 - ELECTRICAL/FRONT WIPERS/WASH-
ERS - INSPECTION) and (Refer to 8 - ELECTRI-
CAL/FRONT WIPERS/WASHERS - CLEANING). For
diagnosis and testing of the multi-function switch
(Refer to 8 - ELECTRICAL/LAMPS/LIGHTING -
EXTERIOR/MULTI-FUNCTION SWITCH - DIAG-
NOSIS AND TESTING). 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.
The hard wired circuits and components of the
front wiper and washer system may be diagnosed
and tested using conventional diagnostic tools and
procedures. However, conventional diagnostic meth-
ods may not prove conclusive in the diagnosis of the
Body Control Module (BCM), or the inputs to or out-
puts from the BCM that control the various front
wiper and washer system operating modes. The most
reliable, efficient, and accurate means to diagnose
the BCM, or the BCM inputs and outputs related to
the various front wiper and washer system operating
modes requires the use of a DRBIIItscan tool. Refer
to the appropriate diagnostic information.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
SIDE CURTAIN AIRBAG, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT 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 COULDRESULT IN ACCIDENTAL AIRBAG DEPLOYMENT
AND POSSIBLE PERSONAL INJURY.
FRONT WASHER SYSTEM
The diagnosis found here addresses an electrically
inoperative front washer system. If the washer
pump/motor operates, but no washer fluid is emitted
from the front washer nozzles, be certain to check
the fluid level in the reservoir. Also inspect the front
washer system components as required. (Refer to 8 -
ELECTRICAL/FRONT WIPERS/WASHERS -
INSPECTION). Refer to the appropriate wiring infor-
mation. The wiring information includes wiring dia-
grams, proper wire and connector repair procedures,
details of wire harness routing and retention, connec-
tor pin-out information and location views for the
various wire harness connectors, splices and grounds.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, DISABLE THE SUPPLEMENTAL RESTRAINT
SYSTEM BEFORE ATTEMPTING ANY STEERING
WHEEL, STEERING COLUMN, DRIVER AIRBAG,
PASSENGER AIRBAG, SEAT BELT TENSIONER,
SIDE CURTAIN AIRBAG, OR INSTRUMENT PANEL
COMPONENT DIAGNOSIS OR SERVICE. DISCON-
NECT 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
AND POSSIBLE PERSONAL INJURY.
(1) Turn the ignition switch to the On position.
Turn the control knob on the right (wiper) control
stalk of the multi-function switch to the On position.
Check whether the front wiper system is operating.
If OK, go to Step 2. If not OK, test and repair the
front wiper system before continuing with these
tests. Refer to FRONT WIPER SYSTEM .
(2) Turn the control ring on the right (wiper) con-
trol stalk of the multi-function switch to the rear
Wash position. Check whether the rear washer sys-
tem is operating. If OK, test the multi-function
switch. (Refer to 8 - ELECTRICAL/LAMPS/LIGHT-
ING - EXTERIOR/MULTI-FUNCTION SWITCH -
DIAGNOSIS AND TESTING). If the multi-function
switch tests OK, go to Step 3. If the multi-function
switch does not test OK, replace the faulty switch.
(3) Turn the ignition switch to the Off position.
Disconnect and isolate the battery negative cable.
Disconnect the headlamp and dash wire harness con-
nector for the washer pump/motor unit from the
pump/motor unit connector receptacle. Check for con-
tinuity between the washer pump driver circuit cav-
8R - 6 FRONT WIPERS/WASHERSKJ
FRONT WIPERS/WASHERS (Continued)

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 oper-
ate 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 Junction Block (JB) to the multi-
function switch through a fused ignition switch out-
put (run-acc) 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 inter-
mittent 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 proce-
dures. 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 posi-
tion 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 cur-rent signal to the rear wiper module through the
rear wiper on driver circuit, causing the rear wiper to
cycle continuously at a fixed speed.
INTERMITTENT WIPE MODE When the Delay
position of the control ring on the right (wiper) con-
trol stalk of the multi-function switch is selected, the
multi-function switch circuitry directs a battery cur-
rent 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 bat-
tery 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/mo-
tor 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 sig-
nal 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 - REAR WIPER &
WASHER SYSTEM
REAR WIPER SYSTEM
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 faulty 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 -
INSPECTION) and (Refer to 8 - ELECTRICAL/
REAR WIPERS/WASHERS - CLEANING). Refer to
the appropriate wiring information. The wiring infor-
8R - 30 REAR WIPERS/WASHERSKJ
REAR WIPERS/WASHERS (Continued)