Lull 944E-42 Service Manual - Manual (Page 191)

9-33 944E-42
Electrical System
b. Fuel Level Circuit Tests
If the fuel level gauge is suspected of giving a false
reading, perform the following checks:
1. Check for loose or defective wiring, faulty ground
connections, and corrosion on the fuel tank level
sender and wiring lead.
2. If the fuel level gauge needle does not move after
the ignition key switch is turned to the RUN position,
use a test lamp to determine whether current is
flowing from the ignition switch to the fuel level
gauge wiring connector behind the operator’s dash
panel.
If the fuel level gauge needle does not move, check
the fuel tank for fuel.
If the fuel level gauge does not move and a faulty or
defective fuel level sender in the fuel tank has been
ruled out, and in addition, wiring and connectors have
been checked and ruled out, the front dash panel is
defective and must be replaced.
3. Check that the ignition terminal has current and that
the fuse in the fuse panel is not blown.
4. Check for broken, shorted, frayed, disconnected or
damaged wiring between the fuel level gauge wiring
at the operator’s dash panel, fuse and relay panel,
ignition key switch, and from the fuel level sender on
the fuel tank through the wiring in the cab.
5. Check the fuel level sender. The resistance of the
fuel sender is 31 ohms for a full tank of fuel, 101
ohms for 1/2 tank and 255 ohms for an empty tank.
A defective fuel level sender in the fuel tank may also
prevent the fuel level gauge from moving.
Excessive fuel level gauge “fluctuation” may be caused
by loose wire connections or a defective fuel level sender
in the fuel tank.
A full tank reading at all times may occur if the wiring to
the fuel level sender in the tank is broken, if the sender is
not properly grounded or if the sender is defective.
If the fuel level gauge appears to be inaccurate, the fuel
sender in the tank may be defective, or there may be low
voltage at the fuel level gauge connector to the operator’s
dash panel.
If the fuel level gauge fluctuates when other electrical
items are used, there may be a defective, corroded or
improper ground. Check the cab harness ground stud
under the dash, the engine to chassis ground, and the
negative (–) battery cable and ground stud cable.
Examine the fuel level sender circuit in Section 9.5,
“Electrical Schematics.”
9.11.15 Hourmeter
The hourmeter (1) is a non-repairable instrument that
records hours of machine engine operation in tenths of an
hour increments and is located in the dash panel.
The hourmeter is an analog device, similar to an
odometer, and will display 99,999.9 hours before
resetting to zero.
If trouble is suspected, time the hourmeter for six minutes
to verify that a tenth of an hour has been recorded.
The hourmeter is built into the dash panel and cannot be
repaired. If the hourmeter is suspect, replace the dash
panel.
0000000
RPM X 100
5
10
15
30
20
25
F
1/2
E 104
176
80
248
120 °C
°F
r/min
D
MU0011
1