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FIFTH-WHEEL OPERATION
WARNING:Failure to follow the fifth-wheel manufacturer’s
instructions for hooking and unhooking as well as sliding the
fifth-wheel could result in an accident, personal injury or death.
WARNING:When the tractor and trailer are parked unattended,
the trailer brake hand control should never be used to apply the
brake, since air may leak from the system, allowing vehicle movement,
resulting in possible property damage, personal injury or death.
Before hook-up, make sure:
•The fifth-wheel jaws are fully opened.
•The fifth-wheel is fully tilted back to prevent body damage when the
tractor is backed under a trailer.
•The trailer wheels are blocked and the trailer spring brakes are
adjusted and applied. Never chase a trailer.
•The brake hoses and light cords are clear of the fifth-wheel.
Hook-up
1. Back the tractor squarely under the trailer, engaging the fifth-wheel
jaws on the kingpin. Always back-up slowly, making sure the trailer is
neither too high nor too low. Avoid backing under the trailer from an
angle.
2. Connect the service and emergency brake hoses and trailer light
connector. Refer toTractor-trailer connectionsin theAir suspension
section of this chapter, adhering to the warning and using the three-point
stance while connecting and disconnecting the trailer.
3. Inspect the jaws of the fifth-wheel to be sure they have fully closed on
the trailer kingpin and the trailer plate is resting securely on the
fifth-wheel.
4. Be sure the coupler release lever is in the locked position.
5. Charge the trailer brake system. Set the trailer brakes, either with the
hand valve or tractor protection valve. Pull against the trailer for an
additional check of proper hook-up. Do not pull hard enough to damage
or strain the equipment.
Driving
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6. Set the tractor parking brakes and fully raise the trailer landing gear.
Refer toBrakesin this chapter for proper operation of the parking brake
and trailer brakes.
7. Check the operation of all trailer lights and correct any lights that may
be faulty.
Un-hook
1. Try to keep the tractor and trailer in a straight line.
2. Apply the parking brakes.
3. Lower the trailer landing gear, making sure it is on solid, level ground.
The weight of the trailer is to be on the landing gear.
4. Block the trailer wheels.
5. Disconnect the brake hoses and light cords. Be sure hoses and cords
are clear.
6. Pull coupler release lever to disengage the fifth-wheel jaws.
7. Release the tractor parking brakes.
8. Pull out from the trailer slowly, allowing the landing gear to take the
load gradually.
Driving
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Fuse/Relay
locationFuse amp
ratingFuse description
15 10A Interior lamp relay
16 15A High beams, Indicator
17 — Not used
18 5A Dimmer switch, Interior lighting
19 15A Engine control (diesel engine only)
20 5A Starting system
21 10A DRL resistor
22 15A Air horn, Air suspension dump, Two-speed
axle, Driver-controlled locking differential
23 10A Flasher relay
24 15A Hydraulic brakes relay, Fuel heater relay
(diesel engine only), Air dryer
25 10A Blower motor relay coil
26 10A Right-hand low beam headlight
27 — Not used
28 10A Left-hand low beam headlight
29 10A Cluster, GEM
30 15A Allison electronic transmission
31 15A Mirror fold relay
Relay 1 — Interior lamps
Relay 2 — Not used
Relay 3 — Horn
Relay 4 — Not used
Relay 5 — Not used
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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
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Fuse/Relay
locationFuse amp
ratingFuse description
304 — DEF (Urea) line heaters relay (diesel engine
only)
— Powertrain control module power VPWR1
(gasoline engine only)
Individual maxi-fuse holder in engine compartment
Fuse
locationFuse amp
ratingFuse description
9925 30A Hydraulic brakes pump motor 1
Relay center
The relay center is located along the passenger side A-pillar on the right
side of the footwell.
Relay
locationRelay description
R1 Spring applied hydraulic release warning chime module or
PCM power VPWR 2, 3 and 4
R2 A/C compressor clutch
R3 Power windows
R4 Flasher (standard/LED)
R5 Upfitter relay 1
R6 Upfitter relay 2
R7 Headlights
R8 Spare
R1
R9 R10 R11 R12 R13 R14 R15 R16 R17
R18 R19 R20 R21 R22 R23 R24 R25 R26
R2 R3 R4 R5 R6 R7 R8
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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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Preparing your vehicle
1.Use only a 12–volt supply to start your vehicle.Do not attach the
jumper cables to the glow plug relay as this could severely damage the
glow plugs, injector driver module and PCM.
2. Do not disconnect the battery of the disabled vehicle as this could
damage the vehicle’s electrical system.
3. Park the booster vehicle close to the hood of the disabled vehicle
making sure the two vehiclesdo nottouch. Set the parking brake on
both vehicles and stay clear of the engine cooling fan and other moving
parts.
4. Check all battery terminals and remove any excessive corrosion before
you attach the battery cables. Ensure that vent caps are tight and level.
5. Turn the heater fan on in both vehicles to protect from any electrical
surges. Turn all other accessories off.
Connecting the jumper cables
1. Connect the positive (+) jumper cable to the positive (+) terminal of
the discharged battery.
Note:In the illustrations,lightning boltsare used to designate the
assisting (boosting) battery.
2. Connect the other end of the positive (+) cable to the positive (+)
terminal of the assisting battery.
+–+–
+–+–
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Removing the jumper cables
Remove the jumper cables in the reverse order that they were
connected.
1. Remove the jumper cable from thegroundmetal surface.
Note:In the illustrations,lightning boltsare used to designate the
assisting (boosting) battery.
2. Remove the jumper cable on the negative (-) connection of the
booster vehicle’s battery.
3. Remove the jumper cable from the positive (+) terminal of the booster
vehicle’s battery.
+–+–
+–+–
+–+–
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