Service Manual User Manual

Electrical System
10-49
Model 3606 • Origin 10/99
10.8 ELECTRICAL SYSTEM COMPONENTS
Electrical components include warning devices such as
the indicators in the operators display panel, horn, back-
up alarm, and other components such as the joystick,
logic panel, various solenoids and all accessories.
Examine the appropriate wiring diagrams and
schematics earlier in this section to help understand the
wiring circuits involved.
10.8.1 Warning Devices
Vehicle warning devices include the horn, instrument
panel warning lights, and the back-up alarm.
a. Horn
The horn (Fig. 10– 40) is mounted forward of the cab on
the vehicle frame.
The horn sounds when the momentary-contact horn but-
ton on the center of the steering wheel is pressed.
Removal of the horn button is discussed in
Section 4.2.4
Controls
of this manual.
Figure 10– 40. Horn location.
The horn sound is produced by a solenoid-actuated dia-
phragm in the horn that develops a resonating air column
in the horn trumpet, which is shaped to project the sound.
If the horn doesn't sound when the horn button is
pressed, check that the fuse is not blown.
Check for corrosion on the horn mounting that may be
preventing a solid ground, and check for a loose horn
wire. Test the horn switch for continuity when the horn
button is pressed.
If the problem is still not located, remove the horn from
the frame and test it using short, heavy-gauge wires con-
nected to a fused or otherwise protected 6-amp minimum
output, 12-volt DC power supply.
b. Warning Indicator Lights
(in operators display panel)
Figure 10– 41. Typical operators display panel
warning indicator lights.
There are eight subdued or "hidden" warning indicator
lights (described below) present in the operators display
panel (Fig. 10– 41). These warning indicators illuminate
during critical circumstances.
IMPORTANT: All eight warning indicator lights demand
immediate attention and vehicle service. In many cases,
the vehicle should be shut down as soon as practical to
help prevent serious mechanical failure. Appropriate ser-
vice procedures for each circuit, as applicable, appear
elsewhere in this section of the manual.
1. Engine Maintenance/Vehicle Lubrication Indicator
This light (item 1, Fig. 10– 41) illuminates every 250 hours
of engine operation to remind the operator that important
maintenance operations are required. After the engine is
serviced (engine oil and engine oil filter changed), the
indicator can be reset by pressing and holding the reset
switch (Fig. 10– 42), then turning the ignition switch to the
RUN position. The indicator light will illuminate during
power-up and will cease to illuminate when it is reset.
The reset switch can then be released. Should there be a
problem with the indicator and it does not cease to illumi-
nate after servicing the engine and conducting the reset
steps above, check the involved circuit and the reset
switch itself for continuity and shorts. Replace a defective
switch. If the problem is determined to exist in the opera-
tors display panel, replace the panel with a new unit.
Figure 10– 42. Typical maintenance reset switch.
MS1830
Horn
1
2
34
F
N
R
D
1
23
4
56
7
8
OS0531
OS0251
Reset Switch