National Crane 1-21-2019 Control # 104-07 3-1
1400A SERVICE MANUAL ELECTRIC SYSTEM
SECTION 3
ELECTRIC SYSTEM
SECTION CONTENTS
Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Jump Starting the Crane . . . . . . . . . . . . . . . . . . . . 3-1
Charging . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
Maintenance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
General . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-1
General Troubleshooting . . . . . . . . . . . . . . . . . . . 3-2
Troubleshooting the Electrical Swivel . . . . . . . . . . 3-2
Connector Troubleshooting . . . . . . . . . . . . . . . . . 3-2
Individual Fuse Holders . . . . . . . . . . . . . . . . . . . . . 3-4
Relay fuse blocks . . . . . . . . . . . . . . . . . . . . . . . . . . 3-4
Micro Relay Fuse Block . . . . . . . . . . . . . . . . . . . . . 3-4
Mini Relay Fuse Block . . . . . . . . . . . . . . . . . . . . . . 3-5
Horn Alarm Circuit . . . . . . . . . . . . . . . . . . . . . . . . . 3-5
VEC Module . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3-6
RCL, ATB, and Crane Manifold Solenoids . . . . . . 3-7
Outrigger Manifolds . . . . . . . . . . . . . . . . . . . . . . . . 3-8
Front Outrigger Manifold . . . . . . . . . . . . . . . . . . . . 3-8
Rear Outrigger Manifold . . . . . . . . . . . . . . . . . . . . 3-8
Hydraulic Oil Cooler . . . . . . . . . . . . . . . . . . . . . . . . 3-9
Hydraulic Temperature Sensor Warning Light . . . 3-9
DESCRIPTION
The truck electrical system is a standard 12 volt DC
automotive type and supplies power for all crane functions.
The wire harness is routed through the torsion box and
contains all wiring interface between the truck and the crane,
including the electrical outrigger controls. The electrical
circuits for crane control functions are routed through an
electrical swivel located in the turret.
When key switch in the operators station is set to RUN, the
throttle pedal in the operators station overrides the truck cab
throttle, the RCL system is powered, and the crane functions
can be activated. The outrigger controls are disabled when
the crane function power switch is on.
JUMP STARTING THE CRANE
Do not attempt to jump start the crane.
All crane models, particularly those produced since 2000,
have multiple computer systems (crane control, RCL, engine
& transmission control) that are highly susceptible to voltage/
amperage surges in the electrical system.
The batteries should be completely disconnected from the
crane electrical system and charged using a battery charger
of appropriate voltage level or replace the batteries with fully
charged batteries.
Charging
When charging the batteries, do not turn on the battery
charger until the charging leads have been connected to the
battery(s). Also, if the battery(s) are found to be frozen, do
not attempt to charge them. Remove the battery(s) from the
crane, allow them to thaw, and then charge the battery(s) to
full capacity.
“Slow charging” is preferred to “fast charging”. Fast charging
saves time but risks overheating the battery(s). Slow
charging at six (6) amps or less develops less heat inside the
battery and breaks up the sulfate on the battery plates more
efficiently to bring the battery up to full charge. The use of a
“smart charger” that automatically adjusts the charging
amperage rate should be used.
MAINTENANCE
General
Electrical system maintenance includes troubleshooting and
replacement of damaged components. Observe standard
wiring practices when replacing components.
CAUTION
It is strongly recommended that the batteries not be
“jumped” with a different vehicle, portable power pack,
etc. The surge of power from these sources can
irreparably damage the various electronic controls and
computer systems. Jump starting the crane batteries with
a different vehicle while the engine is running can damage
the donor vehicle electronics as well if done improperly.
Fo
r
Reference
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