Jeep 1997 Grand Cherokee Service Manual page 1410

8W - 53 - 6
DESCRIPTION AND OPERATION
INTERMITTENT WIPER OPERATION
In the ACCESSORY or RUN position, the ignition
switch connects circuit A1 from fuse 8 in the PDC to
circuit A31. Circuit A31 powers circuit F86 through
the circuit breaker in cavity 1 of the junction block.
Circuit F86 supplies power to the intermittent wiper
switch.
When the operator selects LOW speed wiper oper-
ation, the switch connects circuit F86 to circuit V3.
Circuit V3 powers the wiper motor low speed brush.
When the operator selects HIGH speed wiper oper-
ation, the switch connects circuit F86 to circuit V4.
Circuit V4 powers the wiper motor high speed brush.
When the operator selects intermittent wiper oper-
ation the wiper switch sends a signals to the Body
Control Module (BCM) on circuit V51. The BCM
determines the amount of delay selected on circuit
V50 from the switch.
After determining the amount of delay selected,
the BCM periodically energizes the intermittent
wiper relay on circuit V18. Circuit F86 from the cir-
cuit breaker in the junction block powers the relay
coil and contacts. Circuit F86 is HOT when the igni-
tion switch is in the ACCESSORY or RUN position.
When the intermittent wiper relay energizes it
powers circuit V6. Circuit V6 connects to circuit V3
through the intermittent wiper switch. Circuit V3
powers the wiper motor low speed brush. Circuit Z2
provides ground for the brush. When not energized,
the relay connects circuit F86 to circuit V66. Circuit
V66 connects to the park switch in the intermittent
wiper motor and the BCM.
REAR WIPER/WASHER
The rear wiper and washer system uses a switch
assembly located in the right switch pod.
When the ignition switch is in the ACCESSORY or
RUN position, it connects circuit A1 from fuse 8 in
the Power Distribution Center (PDC) to circuit A31.
Circuit A31 powers circuit V23 through fuse 3 in the
junction block. Circuit V23 supplies power for the
rear wiper/wash switch.
8W - 53 WIPERS
8W-53 WIPERS
Circuit A250 from fuse 11 in the PDC powers cir-
cuit F70 through fuse 8 in the junction block. Circuit
F70 powers the rear wiper motor and the control
module located internal to the motor assembly.
When the operator selects the ON position, power
is supplied through the switch to circuit V13. The
V13 circuit connects from the switch to the rear
wiper control module.
The module processes this signal and supplies
power to the wiper motor. Ground for the wiper
motor is supplied on circuit Z1.
When the switch is placed in the DELAY position,
power is supplied from the switch to the motor con-
trol on circuit V24. The module processes this signal
and connects the motor to voltage. The amount of
DELAY is controlled by the position of the rear wiper
switch.
When the WASH switch is activated, power is
passed through the switch to circuit V20. This circuit
is double crimped at the switch. One branch of the
circuit connects to the rear wiper control module. The
other branch connects to the rear washer pump
motor.
An additional input to the rear wiper control mod-
ule is supplied on circuit G78. This circuit is con-
nected to the liftgate and liftglass ajar switches.
Circuit G78 signals the control when the liftgate or
liftglass opens.
When the liftgate is ajar the wiper control module
will not allow the rear wiper or washer to operate.
HELPFUL INFORMATION
• Check fuses 8 and 11 in the PDC
• Check fuses 3 and 8 in the junction block
• Check the operation of the liftgate ajar switch
LOW WASHER FLUID LEVEL SENSOR
When the switch in the low washer fluid sensor
closes, it connects circuit G29 from the Vehicle Infor-
mation Center (VIC) to ground on circuit Z2. The
VIC displays the low washer fluid message.
ZG