Dodge 2000 DURANGO Service Manual page 190

5 - 36 BRAKES
DESCRIPTION AND OPERATION (Continued)
Fig. 5 Data Link Connector - Typical
1 – 16–WAY DATA LINK CONNECTOR
warning lamp also is used to alerts the driver of a
problem with the RWAL system.
OPERATION
The red brake warning lamp illuminates when a
message is sent over the bus to the cluster to illumi-
nate the bulb. A ground for the bulb is provided
when:
• The parking brake is applied and the park brake
switch is actuated.
• A hydraulic fault has occurred and the pressure
differential switch is actuated.
• A RWAL fault has occurred.
The amber ABS warning lamp is used to alert the
driver of an RWAL problem and identify DTCs stored
in the CABs memory.
BRAKE LAMP SWITCH
DESCRIPTION
The plunger type brake lamp switch is mounted on
a bracket attached to the brake pedal support.
CAUTION: The switch can only be adjusted during
initial installation. If the switch is not adjusted prop-
erly a new switch must be installed.
OPERATION
The primary function of the switch is to turn on
the brake lamps during braking. The switch is also
used to send signals to components that must know
when the brakes are applied, such as the Powertrain
Control Module (PCM), which uses the signal to can-
cel speed control. The CAB uses the brake switch sig-
nal to monitor brake pedal application. When the
switch contacts open (brakes applied), the CAB
receives the brake applied signal. The CAB then
monitors the RWAL system to anticipate the need for
an RWAL stop.
DIAGNOSIS AND TESTING
REAR WHEEL ANTILOCK
Diagnosis of base brake conditions which are
mechanical in nature should be performed first. This
includes brake noise, lack of power assist, parking
brake, or vehicle vibration during normal braking.
The RWAL brake system performs several self-
tests every time the ignition switch is turned on and
the vehicle is driven. The CAB monitors the system
inputs and outputs circuits to verify the system is
operating properly. If the CAB senses a malfunction
in the system it will set a DTC into memory and trig-
ger the warning lamp.
NOTE: The MDS or DRB III scan tool is used to
diagnose the RWAL system. For test procedures
refer to the Chassis Diagnostic Manual. For addi-
tional information refer to the Antilock brake sec-
tion in Group 8W.
RWAL SERVICE PRECAUTIONS
The RWAL uses an electronic control module, the
CAB. This module is designed to withstand normal
current draws associated with vehicle operation.
Care must be taken to avoid overloading the CAB
circuits. In testing for open or short circuits, do
not ground or apply voltage to any of the cir-
cuits unless instructed to do so for a diagnostic
procedure. These circuits should only be tested
using a high impedance multi-meter or the DRB
tester as described in this section. Power should
never be removed or applied to any control module
with the ignition in the ON position. Before removing
or connecting battery cables, fuses, or connectors,
always turn the ignition to the OFF position.
CAUTION: Use only factory wiring harnesses. Do
not cut or splice wiring to the brake circuits. The
addition of after-market electrical equipment (car
phone, radar detector, citizen band radio, trailer
lighting, trailer brakes, ect.) on a vehicle equipped
with antilock brakes may affect the function of the
antilock brake system.
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