Operating Instructions Using the Brake System
Medium Duty
(R10/06) Y53-6008 – 83 –
• If a trailer ABS problem is detected, the lamp
will remain on. The driver should have the
trailer’s ABS problem corrected before the vehi-
cle is driven with that trailer attached.
WARNING! Do not rely on an anti-lock brake sys-
tem that is functioning improperly. You could
lose control of the vehicle resulting in a severe
accident and serious 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 emergency. You will still have conventional
brakes, but not anti-lock brakes. If the lamp indi-
cates a problem, have the ABS checked.
Wheel Spin Control Warning Lamp
Your ABS may have an acceleration slip regulation (ASR) or
automatic traction control (ATC) feature. Either of these fea-
tures is monitored by a wheel spin control warning lamp. This
lamp is located in the warning lamp cluster.
The Wheel Spin Control warning lamp will briefly illuminate
and then go out when the ignition switch is first turned on.
The Wheel Spin Control warning lamp will illuminate when-
ever the ASR or ATC system detects drive wheel spin. The
lamp will remain illuminated as long as wheel spin is detected
and the ASR or ATC system is applying the drive wheel
brakes or reducing engine torque. Do not allow the Wheel
Spin Control lamp to remain on continuously for an extended
length of time. Extended, continuous use of the ASR / ATC
can cause overheating of the drive wheel brakes. Engine
torque or vehicle speed should be reduced to eliminate
wheel spin and prevent excessive application of the ASR /
ATC system.
Except for checking for proper illumination of the ABS and
Wheel Spin Control warning lamps when first starting the
truck and for monitoring these lamps while driving, no special
operating procedures are required. For detailed system
description, see service literature for your specific ABS that
was provided with your vehicle.
Trailer Brake Hand Valve
Tractor/trailer vehicles are equipped with a trailer brake hand
valve mounted on the right side of the steering wheel column.
This hand valve provides air pressure to apply the trailer
brakes only. It operates independently of the foot treadle
valve.
