operators_manual

WARNING
DO NOT rely on an antilock brake sys-
tem
that is functioning improperly. You
could lose control of the vehicle result-
ing in a severe accident, causing per-
sonal injury or death. 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 emergency. You
will still have conventional brakes, but
not antilock brakes. If the lamp indi-
cates a problem, have the ABS
checked.
Vehicles without 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 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 Light (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 light mounted
on the trailer. The indicator light on the
trailer should be yellow and identified
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 T
railer 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 antilock
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
116 Y53-6096-1C1 (09/20)
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