Electrical System
9.32
3507, 3508, 3509, 3512, 3513, 4007, 4008, 4009, 4012, 4013
c. Inspection and Replacement
To determine the proper operation of the ignition key
switch, using the following chart, test the wires on the
back of the switch for continuity with an ohmmeter.
Test the ignition key switch for continuity, by checking
from the ignition
(#30)
wire to each of the following wires
in each switch position. Continuity
(X)
should be present
as indicated in the following chart:
If all connections do not show proper continuity, replace
the ignition switch.
d. Ignition Key Switch Installation
1. Connect the ignition key switch to the cab harness
connectors.
2. Reach up and under the dash to work the ignition
key switch into the ignition key switch mounting hole
on the dash.
3. Align the ignition key switch
4. Connect the battery negative (-) cable to the battery
negative (-) terminal.
5. Close and secure the engine cover.
9.12.10
Fuel Level Indicator and Fuel Level
Sender
a. Fuel Level Indicator Testing
1. The fuel level sender wiring harness leads can be
accessed from the top of the fuel tank. Disconnect
the fuel level sender wiring harness leads. With the
help of an assistant, touch both harness leads
together.
2. From the operator’s cab, have the assistant turn the
ignition key switch to the RUN position.
DO NOT
start the engine. Observe the fuel level indicator
needle on the operator’s instrument cluster.
3. Turn the ignition key switch to the OFF position. The
fuel level indicator needle should return to the
EMPTY position.
b. Fuel Level Circuit Tests
If the fuel level indicator is suspected of giving a false
reading, perform the following checks:
1. If the fuel level indicator needle does not move,
check the fuel tank for fuel.
2. Check for loose or defective wiring, faulty ground
connections or corrosion on the fuel tank sender and
wiring lead.
3. If the fuel level indicator 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
sender.
4. If the fuel level indicator 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
fuel level indicator is defective and must be replaced.
5. Check that the ignition terminal has current and that
the fuse in the fuse panel is not blown.
6. Check for broken, shorted, frayed, disconnected or
damaged wiring between the fuel level indicator
wiring at the cab, fuse and relay panel, ignition key
switch and from the fuel level sender on the fuel tank
through the wiring in the cab.
7. Check the fuel level sender. The resistance of the
fuel level 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 indicator from
moving.
Switch Position
Test from #30 wire to:
OFF
RUN
START
Wire #15
X
X
Wire #50
X
