Troubleshooting guide

42
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Trailer ABS Components and Operation
Trailer ABS Components
Typical Trailer ABS components are:
• Bendix Electronic Control Units (ECUs) such as
the MC-30
™
, A-18
™
, or TABS6
™
Trailer ABS
Controllers
• Wheel Speed Sensors (see page 35)
• Pressure Modulator Valves (also see page 35)
• ABS Indicator Lamps
• Harnesses
Trailer ABS Operation
Examples of trailer ABS systems are:
• Normal braking (operates as a standard relay valve)
• Dolly-axle control (2S/1M), which uses the wheel
behavior monitored by two wheel speed sensors
to modulate the braking of one (or two) axles in
an ABS event
Trailer
Chassis Harness
Trailer ABS
Pigtail Harness
WS Sensor
"SR"
5-PIN
CONNECTOR
Ignition
Power
Brake Light
Power
Ground
7-PIN
CONNECTOR
SUPPL
Y
LINE
CONTROL
LINE
A Brake Light Power
B Ignition Power
C NC
D Indicator Lamp
E Ground
C
E
B
A
D
ABS Indicator Lamp
WS Sensor
"SL"
TABS6™
MOD1
TABS
SR-5™
valve
MOD2
WS Sensor
"SAR"
WS Sensor
"SAL"
Full Trailer
ABS
Example of 4S/2M ABS Trailer Schematic
©2004 Bendix Commercial Vehicle Systems LLC • All Rights Reserved
ABS Lamp
ABS
Harness
See page 35 for
wheel speed sensors
and pressure
modulator valves
MC-30
™
Controller
Assy.
A-18
™
Controller
Assy.
TABS6
™
Controller
Assy.