operators_manual

WARNING
Do not rely on an anti-lock brake sys-
tem that is functioning improperly. You
could lose control of the vehicle result-
ing in a severe accident, causing
death or personal injury. If your ABS
lamp goes on while you are driving or
stays on after the self-check, your anti-
lock system might not be working. The
ABS may not function in an emergen-
cy. You will still have conventional
brakes, but not anti-lock brakes. If the
lamp indicates a problem, have the
ABS checked.
Vehicles without anti-lock brake systems
(ABS) are typically equipped with a bobtail
brake proportioning system. When a trailer
is not connected, the drive axle brake
application pressure will automatically be
limited by the proportioning system. When
driven in a bobtail mode, these tractors will
require greater brake pedal application to
provide the equivalent braking to a bobtail
tractor not equipped with a proportioning
system.
Trailer ABS Power Line
Communication (PLC)
North American on-highway vehicles are
equipped with a separate electrical circuit
to power the anti-lock brake system (ABS)
on towed vehicle(s). In most cases, the
ABS power will be supplied through the
Auxiliary circuit on the primary 7-way trailer
light line connector. If the vehicle was
manufactured with a switchable Auxiliary
circuit for trailer accessories, an additional
7-way connector would have been
provided for trailer ABS power. In either
case, the ABS power line on the vehicle
will be PLC equipped.
CAUTION
DO NOT splice into the non-switchable
Auxiliary circuit on the primary 7-way
trailer light line. Doing so may cause
the trailer ABS to malfunction. This cir-
cuit is dedicated for trailer ABS power.
To add a switchable auxiliary circuit,
contact a dealership.
NOTE
Tractors/Trucks and trailers built after
03/01/2001 must be able to turn on an
In-Cab Trailer ABS Warning Lamp (per
U.S. FMVSS121). The industry chose
Power Line Communication (PLC) as
the standard method to turn it on. On
trailers built prior to 03/01/2001 verify
trailer ABS system status via the re-
quired external warning lamp mounted
on the trailer. The indicator lamp on
the trailer should be yellow and identi-
fied with the letters ABS.
For doubles or triples, the lamp does not
distinguish between trailers. An ABS
problem in any of the trailers will activate
the Trailer ABS Warning Lamp.
If you change the intended service in any
way (e.g., number of axles, multiple
trailers, add switchable trailer accessories,
etc.) from the date the vehicle was
manufactured, you should contact your
trailer manufacturer and/or trailer anti-lock
brake manufacturer to determine if the
power available at the 7-way trailer light
line is adequate. Failure to do so might
result in insufficient power to the trailer
DRIVING - Brakes
Y53-6047-2HEN (03/18) 149
4