Service Manual User guide

9.91
Model 644E-42/944E-42 Rev. 6/04
Electrical System
If
OK
If
OK
Not
OK
Replace failed
solenoid.
Reconnect harness. When
button is pressed, verify that
solenoid AX, is magnetized
by holding a metal object next
to the solenoid. Or, test
resistance in solenoid. Refer
to page 9.233
Repair/replace
single joystick
harness.
Not
OK
Unplug single joystick
harness at hyd joystick
connector and measure
battery voltage at pin A.
Auxiliary hydraulics
do not function.
Wire [AH1] (RED/WHT) is
open. Repair/replace open
cab harness.
Replace fuse.
Plug cab harness back into
single joystick harness, press
button and measure
battery voltage across
solenoid AX, connector wires
[TAA] (TAN) and
[SJG6] (BLK).
Check auxiliary hydraulic
(F10) 5 amp fuse.
Not
OK
Not
OK
Not OK
If OK
If OK
If OK
If OK
Problem is hydraulic.
Refer to Section 8,
“Hydraulic System,”
pages 8.130, 8.132,
8.138 or 8.140.
Check power at wire
[AH1C] (RED/WHT) at single
joystick relay.
Continued on 9.93
Before troubleshooting any
electrical circuit, ALWAYS begin
by checking the following:
1. All connections relating to
circuit are clean and tight.
2. All grounding straps are
intact and securely fastened,
refer to Section 9.1.12,
“General Overview (Vehicle
Ground Strap Locations).”
Not
OK
Verify wire [AHG6] (BLK)
ground connection at cab
ground stud.
Repair/secure ground
connection properly.
If OK
Repair/replace
single joystick
harness.
Not OKIf OK
On single joystick male
connector, verify continuity
across pins 1 and 3 with
button pressed.
Not
OK
At hyd joystick connector,
verify ground connection at
pin C, wire [AHG6] (BLK).
Repair/replace open cab
harness.
If OK
Replace single
joystick relay.
Press button on
single joystick and
verify battery
voltage at wire
[SCO] (YEL) on
single joystick relay.
Not OK
Early Production:
Replace joystick, jumper
harness and control module
with new late production
joystick assembly.
Late Production:
Replace joystick handle.
Single Joystick
Pilot Select Valve Solenoids
Function
Abbreviation
on Valve
Transfer Carriage TR
Auxiliary Hydraulics AX
Extend/Retract EXT
Lift/Lower HO
Attachment Tilt Down CTB
Attachment Tilt Up CTA