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24 VDC ELECTRICAL SYSTEM COMPONENTS
PASSENGER SEAT BASE
COMPARTMENT
The 24 VDC electrical system components shown in
Figure 3-1 are accessed by unlatching the passenger
seat base lid and tilting the passenger seat forward.
The electrical schematics in Section R should be used
when troubleshooting problems with the following
components.
Do not attempt repairs until the truck is properly
shut down. Dangerous voltage levels are present
in the propulsion system while the engine is run-
ning and for a period of time after shutdown. Refer
to Section D Index for additional warnings.
TRUCK SHUTDOWN PROCEDURE
1. Reduce the engine speed to idle. Place the selec-
tor switch in NEUTRAL and apply the parking
brake. Be certain the parking brake applied indi-
cator lamp in the overhead panel is illuminated.
2. Place the drive system in the REST mode by
turning the Rest switch on the instrument panel
ON. Be certain the REST warning lamp is illumi-
nated.
3. Shut down the engine using the keyswitch. If, for
some reason the engine does not shut down, use
the shutdown switch on the center console.
4. Verify the LINK VOLTAGE lights on the electrical
cabinet and next to the the DID panel in the cab
are OFF. If they remain on longer than 5 minutes
after shutdown, the propulsion system must be
inspected by a technician trained to investigate
the cause.
5. Place the GF Cutout Switch in the CUTOUT posi-
tion throughout test and troubleshooting proce-
dures. (See Figure 3-1, page E3-2, Propulsion
System, for switch location.)
6. Verify the steering accumulators have bled down
by attempting to steer.
D03019 04/01
COMPONENTS
TAIL LIGHT RESISTOR DIODE ASSEMBLIES
The tail light resistor diode assembly RD1, RD2 (2,
Figure 3-1) is a circuit designed to vary the intensity of
each of the stop/tail lamp bulbs.
With the tail lights on, a resistor in series with the lamp
reduces voltage supplied to the lamp, thereby reducing
the lamp intensity. When the service brakes are applied
and the stop lights are activated, current flows from the
stop light relay, through a diode, bypassing the resistor
and applies 24 VDC to the lamp filament.
RD1 controls the left lamp and RD2 controls the right
lamp. No adjustments are available or necessary.
5 MINUTE IDLE TIMER COMPONENTS
The 5 minute idle timer circuit automatically provides
approximately 5 minutes engine idle time before actual
engine shutdown occurs. This system allows the en-
gine cooling system to circulate coolant to reduce and
stabilize engine component temperatures, when en-
gine power requirements are minimal, resulting in ex-
tended engine life.
The circuit is controlled by a 3-position rocker switch.
Pressing the bottom of the switch will turn the circuit
OFF. The engine will shut down by use of the Key
Switch, console mounted Engine Shutdown Switch, or
the Ground Level Shutdown Switch.
With the rocker switch in the middle position, the circuit
is ON, but does not activate the 5 minute idle timer
circuit. The engine can be shut down immediately
using any one of the three switches described above.
When the top of the switch is depressed and held
momentarily, the idle timer circuit is activated. When
released, the switch will return to the ON (middle)
position, and the 5 minute idle timer circuit is latched
on through the switch. The engine will not shut down
with the Key Switch. Moving the Key Switch to the OFF
position, will cause the engine to shut down after the 5
minute time delay is completed. The normal shutdown
sequence will then occur.
However, if during the 5 minute idle timing sequence,
the 5 minute delay switch (on the instrument panel) is
pressed to the OFF position, the console shutdown
switch is depressed, or the Ground Level Shutdown
switch is activated, the engine will shut down immedi-
ately, followed by the normal shutdown of all systems.
24VDC System Components
D3-1
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Table of Contents
Troubleshooting
