Jeep 1996 Grand Cherokee Service Manual - page 578
8W-35 ALL-WHEEL ANTI-LOCK BRAKES
INDEX
page
page
DESCRIPTION AND OPERATION
ABS MAIN RELAY . . . . . . . . . . . . . . . . . . . . . . . . 1
ABS PUMP MOTOR RELAY . . . . . . . . . . . . . . . . . 1
ABS WARNING LAMP . . . . . . . . . . . . . . . . . . . . . 2
DATA LINK CONNECTOR . . . . . . . . . . . . . . . . . . . 2
G-SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HYDRAULIC CONTROL UNIT . . . . . . . . . . . . . . . . 2
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 1
STOP LAMP SWITCH INPUT . . . . . . . . . . . . . . . . 2
WHEEL SPEED SENSORS . . . . . . . . . . . . . . . . . 1
SCHEMATICS AND DIAGRAMS
WIRING DIAGRAM INDEX . . . . . . . . . . . . . . . . . . 2
DESCRIPTION AND OPERATION
INTRODUCTION
Several fuses supply power for the Anti-Lock Brake
System (ABS); fuses 5, 8, 11 and 14 in the Power
Distribution Center (PDC) and fuses 5, 9, 11 in the
junction block. Fuses 5, 8, 11 and 14 in the PDC are
connected directly to battery voltage and are HOT all
times. Fuse 5 in the junction block is HOT when the
ignition switch is the START or RUN position. Fuse
11 in the junction block is HOT when the ignition
switch is in the RUN position. Fuse 9 in the junction
block is HOT at all times.
In the RUN position, the ignition switch connects
circuit A1 from fuse 8 in the PDC with circuit A22.
Circuit A22 feeds circuit F12 through fuse 11 in the
junction block. Circuit F12 connects to the coil side of
the ABS main relay and the Controller, Anti-Lock
Brakes (CAB).
Circuit Z2 provides ground for the CAB. Circuit Z2
connects to cavities 14 and 13 of the CAB.
Refer to group 5, Brakes for operational descrip-
tions of ABS system components.
WHEEL SPEED SENSORS
The all wheel anti-lock system uses four wheel
speed sensors; one for each wheel. Each sensor con-
verts wheel speed into an electrical signal that it
transmits to the Controller, Anti-Lock Brakes (CAB).
A pair of twisted wires connect to each sensor to pro-
vide signals to the CAB.
Circuits B6 and B7 provide signals to the CAB
from the right front wheel speed sensor. Circuit B6
which provides the LOW signal connects to cavity 2
of the CAB. Circuit B7 connects to cavity 1 of the
CAB and provides the HIGH signal.
Circuits B8 and B9 provide signals to the CAB
from the left front wheel speed sensor. Circuit B8,
which provides the HIGH signal, connects to cavity
10 of the CAB. Circuit B9 connects to cavity 9 of the
CAB and provides the LOW signal.
Circuits B1 and B2 provide signals to the CAB
from right rear wheel speed sensor. Circuit B1 which
provides the LOW signal connects to cavity A11 of
the CAB. Circuit B2 connects to cavity A12 and pro-
vides the HIGH signal.
Circuits B4 and B3 provide signals to the CAB
from the left rear wheel speed sensor. Circuit B3,
which provides the LOW signal, connects to cavity A9
of the CAB. Circuit B4 connects to cavity A10 and
provides the HIGH signal.
G-SWITCH
During four-wheel drive operation, the G-switch
provides deceleration data to the Controller, Anti-
Lock Brakes (CAB). Refer to Group 5, Brakes for
additional information.
Circuits B41, B42, and B43 connect the G-switch to
the CAB. Circuits B41 and B42 provide switch states
while circuit B43 provides ground. At the CAB, cir-
cuit B41 connects to cavity A6, circuit B42 connects
to cavity A7 and circuit B43 connects to cavity A2.
ABS MAIN RELAY
The ABS main relay is located in the Power Distri-
bution Center (PDC). When the Controller, Anti-Lock
Brakes (CAB) grounds the ABS main relay coil on
circuit B58, the relay switches to connect circuit A20
from PDC fuse 14 to circuit B47. Circuit F12 from
fuse 11 in the junction block splices to feed the coil
side of the ABS main relay. Circuit B58 connects to
cavity 11 of the CAB.
Circuit B47 splices to power to the coil side of the
ABS pump motor relay. Other branches of circuit B47
connects to cavity 5 of the CAB and to the hydraulic
control unit.
ABS PUMP MOTOR RELAY
The ABS pump motor relay in the power distribu-
tion center (PDC) supplies voltage to the ABS pump
motor. When the ABS main relay energizes, circuit
B47 supplies battery voltage to the coil side of the
ABS pump motor relay. The Controller, Anti-Lock
ZJ
8W - 35 ALL-WHEEL ANTI-LOCK BRAKES
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