Jeep 1997 Grand Cherokee Service Manual page 1267

ZG
DESCRIPTION AND OPERATION
ABS WARNING LAMP . . . . . . . . . . . . . . . . . . . . . 5
DATA LINK CONNECTOR . . . . . . . . . . . . . . . . . . 5
G-SWITCH . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
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 fuse 9 and 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 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 Controller,
Anti-Lock Brakes (CAB).
Circuit Z2 provides ground for 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.
Circuits B8 and B9 provide signals to the CAB
from the left front wheel speed sensor.
Circuits B1 and B2 provide signals to the CAB
from right rear wheel speed sensor.
Circuits B4 and B3 provide signals to the CAB
from the left rear wheel speed sensor.
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.
8W - 35 ALL-WHEEL ANTI-LOCK BRAKES
8W-35 ALL-WHEEL ANTI-LOCK BRAKES
INDEX
page
INTRODUCTION . . . . . . . . . . . . . . . . . . . . . . . . . 5
STOP LAMP SWITCH INPUT . . . . . . . . . . . . . . . 5
WHEEL SPEED SENSORS . . . . . . . . . . . . . . . . . 5
Circuits B41, B42, and B43 connect the G-switch to
the CAB. Circuits B41 and B42 provide switch states
while circuit B43 provides ground.
ABS WARNING LAMP
Circuit F87 from fuse 5 in the junction block pro-
vides power for the ABS warning lamp in the instru-
ment cluster. Ground for the ABS warning lamp is
provided by the Controller, Anti-Lock Brakes (CAB).
The CAB illuminates the lamp by providing ground
on circuit 205.
HELPFUL INFORMATION
When the ignition switch is in the START or RUN
position, it connects circuit A1 from fuse 8 in the
Power Distribution Center (PDC) to circuit A21. Cir-
cuit A21 powers circuit F87 through fuse 5 in the
junction block.
STOP LAMP SWITCH INPUT
Circuit L50 from the stop lamp switch provides the
brake switch input to the Controller, Anti-Lock
Brakes (CAB). When the brake pedal is depressed,
the stop lamp switch closes to supply battery voltage
from circuit L16 to circuit L50. Circuit L50 connects
to the CAB. Circuit L16 originates at fuse 9 in the
junction block. Circuit A250 from fuse 11 in the
Power Distribution Center (PDC) supplies power to
junction block fuse 9.
DATA LINK CONNECTOR
Circuit D83 from cavity A3 of the Controller, Anti-
Lock Brakes (CAB) transmits data to the DRB scan
tool through the data link connector. Through the
data link connector, circuits Z1 and Z2 provide
ground for the DRB scan tool.
Circuit F75 supplies battery voltage to the scan
tool through the diagnostic connector.
8W - 35 - 5
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