Dodge RAM TRUCK 1500 1995 Service Manual page 629

8W - 32 - 4
8W-32 REAR WHEEL ANTI-LOCK BRAKES
BR
• Circuit B243 connects to cavity 35 of the ABS con­
trol module and provides ground for the left front
dump solenoid.
• Circuit B245 connects to cavity 37 of the ABS con­
trol module and provides ground for the left front iso­
lation solenoid.
There are two reset switches in the front anti-lock
valve; a left switch and a right switch, both provide
inputs to the ABS control module. Circuit B5 from
the left reset switch connects to ABS module cavity 5
while circuit B18 from the right reset switch connects
to cavity 18.
HELPFUL INFORMATION
The front anti-lock valve is case grounded.
REAR ANTI-LOCK VALVE
Circuit B120 from the ABS pump relay supplies
voltage for the isolation and dump solenoids in the
rear anti-lock valve. The ABS control module acti­
vates the solenoids by providing separate ground
paths for each.
• Circuit B254 connects to cavity 26 of the ABS con­
trol module and provides ground for the right rear
dump solenoid.
• Circuit B252 connects to cavity 28 of the ABS con­
trol module and provides ground for the right rear
isolation solenoid.
The rear anti-lock valve has one reset switch that
provides an input to the ABS control module. Circuit
B19 from the reset switch connects to ABS control
module cavity 19.
ABS WARNING LAMP
The ABS control module operates the ABS yellow
warning lamp through the ABS warning lamp relay.
When the ABS module grounds the warning lamp re­
lay on circuit B47, the relay contacts close and com­
plete the ground path for the ABS warning lamp.
Circuit B47 connects to pin 13 of the ABS module
and the coil side of the relay. Circuit A20 from fuse
14 in the fuse block supplies power to the coil side of
the relay.
Circuit G19 from the ABS warning lamp in the in­
strument cluster is double crimped at the contact
side of the ABS warning lamp relay. Power for the
bulb is supplied by the printed circuit board in the
instrument cluster. The G19 branch leaving the relay
provides an input to the ABS control module at cav­
ity 24 of the module. Circuit Zl provides a ground
path for the contact side of the relay.
BRAKE WARNING LAMP SWITCH INPUT
Circuit G9 provides an input to the ABS control mod­
ule. The module receives the input when either the ig­
nition switch is in the START position, the park brake
switch CLOSES or the brake warning lamp switch in
the hydraulic combination valve CLOSES.
STOP LAMP SWITCH SENSE
On circuit V40, the ABS control module senses
when the brake pedal has been depressed. Circuit
V40 connects to cavity 9 of the ABS control module
and splices to the stop lamp switch and the Power-
train Control Module (PCM).
FOUR-WHEEL DRIWE/PTO SWITCH SENSE
From circuit G107, the ABS control module senses
when the four-wheel drive/PTO indicator lamp switch
closes. Circuit G107 connects to cavity 8 of the ABS
control module and splices to the four-wheel drive/
PTO indicator lamp switch and instrument panel
four-wheel drive/PTO indicator lamp indicator lamp.
ABS DATA LINK CONNECTOR
The DRB scan tool connects to the ABS data link
connector. Circuits Dll and D12 from the ABS con­
trol module connect to the data link connector. Cir­
cuit D12 connects to cavity 10 of the ABS control
module. The ABS control module transmits data to
the DRB scan tool on circuit D12.
The DRB scan tool receives data from the ABS con­
trol module on circuit Dll. Circuit Dll connects to
cavity 11 of the ABS control module.
WACUUM SWITCH
The vacuum switch is used on the diesel engine
only. Power for the switch is supplied on circuit A20.
This circuit is HOT in the RUN position only and
protected by a 20 amp fuse located in cavity 14 of the
fuse block.
Ground for the switch is supplied on circuit Zl.
Circuit G9 connects to the vacuum switch and sup­
plies a ground path for circuit G9. If there is a prob­
lem in the system, the switch grounds circuit G9 and
the red brake warning lamp in the instrument clus­
ter is illuminated.
DIAGRAM INDEX—ANTI-LOCK BRAKES
Component Page
ABS Control Module 8W-32-9 thru 13
ABS Pump Relay 8W-32-9
ABS Warning Lamp Relay 8W-32-9
Data Link Connector 8W-32-11
Front Anti-Lock Valve . . 8W-32-10
Front Wheel Speed Sensor . 8W-32-11
Fuse 2 (PDC) . . . . . .8W-32-12
Fuse 14 (Fuse Block) . .8W-32-9, 12
Ignition Switch 8W-32-9, 12, 13
Instrument Cluster 8W-32-9
Rear Anti-Lock Valve 8W-32-9
Rear Wheel Anti-Lock Brake Sensor 8W-32-11
Vacuum Sensor 8W-32-12