Lull 944E-42 Service Manual - Manual (Page 739)

9.229 Model 644E-42/944E-42 Rev. 6/04
Electrical System
c. Front Joystick Function Solenoid Valves
The front joystick commands are actuated, both
electrically and hydraulically, via a set of solenoid-
operated cartridges within the pilot select valve (15). The
pilot select valve is located on the valve plate which is
located under the cab floor.
As the solenoid coils (16) are energized/de-energized,
the cartridges open and close oil passages, thereby
directing hydraulic fluid flow between the transaction
section or to the auxiliary hydraulic section of the main
control valve
d. Solenoid Coil and Cartridge Valve Replacement
If a solenoid coil (16) is suspected of malfunctioning,
disconnect the coil wiring lead (17) and test the coil for
proper resistance (8-12 ohms). Replace solenoid if open
or shorted to ground. Also inspect the valve cartridges,
o-rings, and the other hydraulic and electrical
components in the circuit to accurately determine the
cause of the problem.
The solenoid coils are of the same design. If testing both
coils, insure that the coil wiring connectors are correctly
re-connected.
9.14.11 Optional Single Joystick
This vehicle can be equipped with an optional single
joystick.
The single joystick option is an assembly containing a
single joystick (18) to control boom functions, auxiliary
hydraulics, attachment tilt and the PlaceAce™ transfer
carriage operation. The frame sway is controlled by a
separate frame sway joystick (19) which is located behind
the single joystick assembly.
The joystick can be operated in two separate modes of
operation: without button (20) depressed “Boom Lift/
Lower and Extend/Retract” (Default Mode) and with
button (20) depressed and held “Transfer Carriage
Extend/Retract and Auxiliary Hydraulic Male
Pressurized/Female Pressurized” (Secondary Mode).
The joystick also has a thumb control (21), on the topside
of the joystick, for attachment tilt control which operates
in either mode.
IMPORTANT: The button (20) must be held against the
joystick handle during operation of the Secondary Mode.
Releasing the button (20) from the Secondary Mode will
immediately change the joystick back to the Default
Mode of operation.
Two functions can be accomplished at the same time by
moving the joystick in between quadrants. For example,
moving the joystick forward will lower the boom, and
moving the joystick to the left will retract the boom;
moving the joystick forward and to the left will both lower
and retract the boom at the same time.
The speed of movement relates to the amount of joystick
movement away from the center position. The overall
speed of movement also depends directly on engine rpm.
MU4050
16
15
17
OU1201
18
19
20
21