Lull 944E-42 Service Manual - Manual (Page 740)

Electrical System
9.230 Model 644E-42/944E-42 Rev. 6/04
Joystick mode operation can be checked according to the
joystick operation instructions found in the Owners/
Operators Manual for this vehicle. Operational checks will
indicate whether the system is working properly. If a
designated function does not occur as described, check
both the electrical and hydraulic circuit involved to
determine the cause.
If the “Boom Lift/Lower and Extend/Retract” (Default
Mode) is functioning correctly, the problem is not
hydraulic. The problem is either in the vehicle cab
harness (4), the joystick harness (5), the solenoids on the
single joystick pilot select valve (6), the joystick control
module (7) (early production only), control module jumper
harness (8) (early production only) or the joystick
handle (9). If the joystick harness and the solenoids on
the control valve are functioning properly, the problem is
in the joystick control module (early production only),
control module jumper harness (early production only) or
the joystick handle. The early production single joystick
with control module and jumper harness are not
serviceable. All three pieces must be replaced with a new
single joystick assembly. Refer to the proper Parts
Manual for correct part number.
a. Single Joystick Harness Testing
1. Remove the capscrews and washers (1) securing
the right side access panel (2) and joystick mounting
console (3).
Determine whether you have an early or late production
single joystick. The early production single joystick has a
separate control module (7) and jumper harness (8)
between the single joystick harness (5) and the joystick
connector (10).
The late production single joystick has the single joystick
harness connector (11) plugged directly into the joystick
connector (10).
2. Disconnect the single joystick harness
connector (12) from the vehicle cab harness. Check
the vehicle cab harness 3 pin connector (4) with a
DMM for battery voltage. Place the negative (-) lead
on pin C (ground) and the positive (+) lead on the
pin A, and test for battery voltage.
If battery voltage is not present, the vehicle cab
harness is suspect and should be replaced. If battery
voltage is present, the vehicle cab harness is
functioning properly.
3. Disconnect the single joystick harness
connector (11) from the joystick connector (10) or
the control module jumper harness connector (13).
Check the single joystick harness 6 pin
connector (11) with a DMM for battery voltage. Place
the negative (-) lead in pin 2 (ground) and the positive
(+) lead on the pin 1, and test for battery voltage.
If battery voltage is not present, the single joystick
harness (5) is suspect and should be replaced. If
battery voltage is present, the single joystick harness
is functioning properly.
MU6210
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1
2
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3
MU6240
4
5
6
7
8
9
10
11
12
13
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