operators_manual

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 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 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
ABS system, which may affect its
operation.
CAUTION
The center pin of the 7-way trailer light
line may be constantly powered for
ABS. Make sure it will not accidentally
turn on trailer equipment.
Special Trailer ABS Without PLC
(Option)
If a trailer does not have PLC, but it does
have ABS that is powered through an
optional second trailer connector (ISO
3731) and that trailer ABS is designed to
control the Trailer ABS Warning Lamp in
the cab and the vehicle has been ordered
with the option to turn on this lamp for
these types of trailers, then this lamp will
turn on when that trailer ABS has a system
problem. This should be checked by a
dealer as soon as possible. The Trailer
ABS Warning Lamp will not turn on for the
power-on test when connected to these
types of trailers.
DRIVING - Brakes
162 Y53-6126-1A1 (01/21)
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