fluid condition exists the switch will close, grounding
the low fluid circuit and illuminating the Red Brake
Warning Lamp. The (CAB) will disable the Anti-Lock
Function and light the Amber Anti-Lock Warning
Lamp if the vehicle is in motion above 3 mph. If the
vehicle is not in motion, the Amber Anti-Lock Warning
Lamp will NOT be lit.
PUMP/MOTOR ASSEMBLY
The Pump/Motor Assembly is mounted to the tran-
saxle below the hydraulic assembly,(Fig. 3). Integral to
the Pump/Motor Assembly is an accumulator using a
sliding piston configuration with a nitrogen pre-charge
of 3,172 kPa (460 psi.) The Pump/Motor is an electri-
cally driven pump that takes low pressure brake fluid
from the hydraulic assembly fluid reservoir and pres-
surizes it. The pressurized fluid is then stored in the
piston accumulator and hydraulic bladder accumulator
for power assist and Anti-Lock Braking. Operation of
the Pump/Motor is controlled by the Dual Function
Pressure Switch through the Pump/Motor Relay. The
(CAB) does NOT control the Pump/Motor activa-
tion. Rubber isolators are used to mount the pump to
its bracket for noise isolation. The Pump/Motor Assem-
bly is connected to the Hydraulic Assembly with a low
pressure return hose and a high pressure hose. A filter
is located in the low pressure return line.
WHEEL SPEED SENSORS
One Wheel Speed Sensor (WSS), is located at each
wheel (Fig. 4, 5 and 6) and sends a small (AC) electrical
signal to the control module (CAB). This signal is
generated by magnetic induction. The magnetic induc-
tion is created when a toothed sensor ring (Tone Wheel)
passes by the stationary magnetic (Wheel Speed Sen-
sor). The (CAB) converts the (AC) electrical signal
generated at each wheel into a digital signal. If a wheel
locking tendency is detected, the (CAB) will then
modulate hydraulic pressure to prevent the wheel(s)
from locking.
The front Wheel Speed Sensor (Fig. 4) is mounted to
a boss on the steering knuckle, for both the Front
Wheel Drive and All Wheel Drive applications. The
Tone Wheel is part of the outboard constant velocity
joint housing.
The Rear Wheel Speed Sensor, on Front Wheel Drive
applications.
Is
mounted
to
the
rear
brake
PRESSURE SWITCH AND PRESSURE TRANSDUCER WIRING
Fig. 3 Pump/Motor Assembly And Heat Shield
.
ANTI-LOCK BRAKES
5 - 63