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WARNING:Do not drive with your foot resting on the brake
pedal. This results in abnormally high brake temperatures,
excessive lining wear and increased stopping distances.
Before descending a long or steep hill, shift to a lower gear and avoid
continuous application of the brakes. Normally, choose the same gear to
descend the hill that you use to ascend the hill.
WARNING:Continuous application of the brakes causes the
brakes to overheat, resulting in a temporary loss of braking.
If brakes do not grip well
•If you have been driving through deep water, gently apply the brakes
several times while the vehicle is moving slowly.
•Let the brakes cool if you have been using them excessively, as in
mountain driving or after several fast, high-speed stops.
•Check brake adjustment.
•Check brake linings for excessive wear.
•Check system air pressure on vehicles equipped with air brakes.
HYDRAULIC BRAKES (IF EQUIPPED)
Full Power Brake System
This system incorporates standard braking, an anti-lock braking system
(ABS) and optional Power Park Brake into one fully-integrated hydraulic
brake system. With the Full Power Brake System, braking energy is
stored, similar to an air brake system, resulting in faster response times
and shorter stopping distances. This is accomplished using motor/pump
assemblies that pressurized the system by pumping brake fluid into
accumulators. This is similar to the air compressor of an air brake system
pressurizing the air tanks. The system includes a master cylinder that
provides the normal pedal “feel” and transfers the pedal force, via brake
fluid, to the main components of the system.
Note:The motor/pumps run momentarily with the ignition switch in the
on or run positions or the switch is in the off position and the brake
pedal is pressed.
Driving
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Actuation of trailer park (emergency) or tractor bobtail position
To actuate the trailer brakes only, pull out the trailer air supply knob (1).
The trailer brakes are now applied whether emergency or spring brakes
are used on the trailer.
This mode is also used when the tractor or truck with trailer is used
during bobtail operation.
ANTI-LOCK BRAKE SYSTEM (ABS)
Your vehicle is equipped with an anti-lock braking system (ABS). This
system helps you maintain steering control during emergency stops by
keeping the brakes from locking. Noise from the ABS pump motor and
brake pedal pulsation may be observed during ABS braking; any
pulsation or mechanical noise you may feel or hear is normal.
When hard braking is required, apply continuous force on the brake
pedal. Do not pump the brake pedal since this reduces the effectiveness
of the ABS and increases your vehicle’s stopping distance. The ABS
activates immediately, allowing you to retain steering control during hard
braking and on slippery surfaces. However, the ABS does not decrease
stopping distance.
ABS warning light
The
light in the instrument cluster momentarily illuminates when the
ignition is turned on. If the light does not illuminate during start up,
remains on after the vehicle reaches 5–10 mph (8–16 km/h), or flashes,
the ABS may be disabled and may need to be serviced.
Even when the ABS is disabled, normal braking is still effective. If
the
light illuminates with the parking brake released, have your
brake system serviced immediately.
1
2
Driving
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Power distribution box
WARNING:Always disconnect the battery before servicing high
current fuses.
WARNING:To reduce risk of electrical shock, always replace
the cover to the Power Distribution Box before reconnecting the
battery or refilling fluid reservoirs.
Fuse/Relay
locationFuse amp
ratingFuse description
1 20A Upfitter switches (AUX 2 and AUX 4)/Trailer
12V socket pin
2 30A Power seat (driver)
3 30A Power seat (passenger)
4 15A Windshield washer relay, Washer pump motor
5 5A Brake warning switch (hydraulic brake only)
6 20A Upfitter switches (AUX 1 and AUX 3)
7 15A Brake pressure switches, ABS event relay
8 20A DEF (Urea), Line heaters (diesel engine
only)
9 20A Ignition switch, Starter cutoff
503
502
501304
303
302 301
2119 22 2024
23401
207 201202 203204
209 206
208 205602
601118114
110106
102
117 113 109105
101
116 112 108104
115 111 107103
18 16
14 12 10 864
2
17 15
13 11 9 753
1
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Fuse/Relay
locationFuse amp
ratingFuse description
10 15A Air tank moisture removal valve
11 30A Electric trailer brake
12 20A Passenger compartment fuse box 5 and 21
13 15A Instrument cluster/Gateway module
14 20A Nitrogen oxide sensor (diesel engine only)
15 — Not used
16 5A BendixAir ABS
17 — Not used
18 10A Fuel transfer pump
19 15A Powertrain control module power 1 (gasoline
engine only)
20 10A Powertrain control module power 2 (gasoline
engine only)
21 20A Powertrain control module power 3 (gasoline
engine only)
22 20A Powertrain control module power 4 (gasoline
engine only)
23 — Not used
24 10A Powertrain control module keep-alive power
(gasoline engine only)
101 30A Bendix Air ABS relay (Air brake vehicles
only)
Hydraulic brakes module (Hydraulic brake
vehicles only)
102 20A Ignition switch
103 20A Ignition switch, Passenger compartment fuse
box fuses 19, 29 and 30
104 20A Power point
105 20A Power door lock switches
106 30A Main light switch, Multi-function switch
107 50A Passenger compartment fuse box fuses 1, 2,
3, 4, 12, 13, 14 and 15
Roadside Emergencies
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Fuse/Relay
locationFuse amp
ratingFuse description
108 40A Fuel heater (diesel engine only)
20A Fuel pump module (gasoline engine only)
109 40A Power window
110 30A Windshield wiper
111 30A Body builder relay, Parking lamps
112 40A Blower motor
113 30A Heated seats, Air-Ride seat
114 20A Aftertreatment DCU
115 20A Ignition switch, Passenger compartment fuse
box fuses 8, 9, 10 and 11
116 30A Left/Right turn relays, Back-up lamp relay
117 20A Stoplamps
118 60A Hydraulic brake vehicles (Trailer tow package
only)
601 60A Trailer socket
602 60A Air brake trailer tow fuse block
30A Hydraulic brakes pump motor 2
201 — Windshield washer relay
202 — Wiper high/low relay
203 — Wiper run/park relay
204 — Windshield wiper relay
205 — Body builder relay, right turn
206 — Body builder relay, left turn
207 — ABS event relay (Hydraulic brake vehicles
only)
208 — Body builder relay, back-up lamps relay
209 — Auxiliary stoplamp relay
301 — Fuel heater/Fuel transfer pump relay (diesel
engine only)
— Fuel pump module (gasoline engine only)
302 — Body builder relay, parking lamps relay
303 — Blower motor relay
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Relay
locationRelay description
R9 Upfitter relay 3
R10 Starter
R11 DCU (diesel engine only)
R12 Two–speed axle/Differential lock
R13 Door lock
R14 Air tank moisture valve
R15 DRL #1
R16 Heated mirrors
R17 Spare
R18 Upfitter relay 4
R19 Shift interlock/EPRNDL display
R20 Selective Catalyst Reduction (SCR) system (NOx) (diesel
engine only)
R21 Run
R22 Door unlock
R23 ABS warning indicator
R24 DRL #2
R25 Park lights
R26 Spare
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Trailer tow relays (if equipped)
Fuse/Relay
LocationFuse Amp
RatingDescription
1 30A* Trailer tow ABS feed (non electric trailer
brake vehicles only)
2 30A* Trailer tow park/marker lamps
3 30A* Trailer tow stop lamps
4 30A* Trailer tow turn/stop lamps (combined)
Trailer tow turn lamps (separate)
5 — Not used
R1 — Trailer tow ABS relay (non electric trailer
brake vehicles only)
R2 — Trailer tow marker lamp relay
R3 — Trailer tow stop lamp relay
R4 — Trailer tow tail lamp relay
R5 — Not used
R6 — Not used
R7 — Trailer tow left turn lamp relay
R8 — Trailer tow right turn lamp relay
*Maxi fuse
Roadside Emergencies
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Air dryer:Climactic conditions affect performance of desiccant or
after-cooler type air dryers. Maintenance schedules must be established
for each specific operation.
The use of an air dryer on a vehicle does not eliminate the need to
periodically drain the air reservoirs.
Desiccant air dryer:Inspect for moisture in the air system by opening
reservoirs, draincocks or valves and checking for presence of water. The
presence of small amounts of water due to condensation is normal and
should not be considered as an indication that the dryer is not
functioning properly.
The desiccant cartridge should be replaced or rebuilt when it has been
determined that the desiccant is contaminated and does not have
adequate water absorption capacity. The desiccant change interval may
vary; it is generally recommended that the desiccant be replaced every
12 months (yearly). If experience has shown that extended or shortened
life has resulted for a particular installation, then the yearly interval can
be increased or decreased accordingly.
Hydraulic brakes
Inspection and adjustment:Establish a regular schedule for periodic
cleaning, lubrication and adjustment inspection based on vehicle use.
Exact maintenance intervals are difficult to predetermine since vehicles
are used in a wide variety of applications and conditions; if you are
uncertain of the proper schedule for your vehicle, contact your dealer.
Inspect the brake lining every maintenance interval. Establish inspection
intervals that provide for lining replacement before damage to the disc
occurs. Excessive lining wear may expose the backing plate to the disc
causing scoring of the disc faces. This inspection should be performed by
a qualified technician and must be in accordance with instructions
provided by the service manual. Hydraulic brake systems are
power-assisted. Braking capabilities are greatly reduced without engine
assist.
Fluid level:Fluid level should be at the bottom edge of the ring on each
reservoir fill port. Do not fill the master cylinder to the top of the
reservoir. If fluid level requires attention to maintain a proper master
cylinder level, this is an indication of either severe operation (pad wear)
or fluid leakage. A more frequent and thorough brake inspection is
required.
Maintenance and Specifications
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