National Crane 1-21-2019 Control # 104-07 3-5
1400A SERVICE MANUAL ELECTRIC SYSTEM
Mini Relay Fuse Block
The mini relay fuse block is located on the right and contains
the following components:
• R1 - Accessory relay supplies power to micro fuse block
F1 through F10 when energized by the crane ignition
switch.
• R2 - Crane power relay supplies power to mini fuse
block F1 through F10 when energized by the crane
power switch.
• R3 - Supplies power to the RCL dump solenoids when
not at capacity, not two-blocked, or when overridden.
• F1 - Main hoist burst of speed circuit.
• F2 - Spare
• F3 - Park Brake Release circuit for the swing brake
switch on the crane cab console.
• F4 - Auxiliary hoist circuit (optional).
• F5 - Auxiliary hoist high speed circuit (optional)
• F6 - Main hoist rotation indicator circuit.
• F7 - Outrigger Lockout circuit disables the outriggers
when the crane function power switch is on.
• F8 - Cab Outrigger circuit for outrigger control from the
crane cab (optional).
• F9 - RCL dump valve solenoid circuit.
• F10 - Switch LED’s on the crane cab console.
Horn Alarm Circuit
The horn alarm sounds in the following conditions:
• The operator depresses the horn switch on the front
console.
• The operator leaves the operators seat without turning
off the crane function power switch.
• The operator depresses the horn switch in the left
armrest.
Mini Relay Fuse Block
FIGURE 3-3
Fault Check
Horn switch does not
activate horn
• Fuse F2 in micro fuse block
• Horn switch
Seat safety switch
does not activate horn
• Fuse holder in crane cab
console (Figure 3-1 Item 5)
• Horn relay R4 in micro fuse
block
• Horn alarm relay R3 in micro
fuse block
Armrest horn switch
does not activate horn
• Fuse F2 in micro fuse block
• Horn switch
Fo
r
Reference
Only