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5 Minute Idle Timer
The 5 minute idle timer (6) circuit is activated when the
operator presses the 5 minute idle timer engine shut-
down switch mounted on the instrument panel. (This is
a momentary switch that also latches the 5 minute idle
timer in the energized position.) When the timer is
energized, internal contacts close and energize the
relay and contactor described below.
5 Minute Idle Relay
The relay (12) contacts close when the idle delay timer
is energized. When the contacts are closed, the AID
system "5 minute idle timer" indicator lamp circuit
(23LI) on the overhead display is grounded, turning the
lamp on.
5 Minute Idle Contactor
The contactor (7) energizes the idle timer and main-
tains current flow to the engine "run" circuit if the
operator turns the key switch off.
5 Minute Idle Circuit Test
Check 5 minute idle timer circuits as follows:
1. With the key switch ON, press the Engine Shut-
down switch firmly to the momentary position and
release (switch will return to the ON position).
2. Turn the key switch OFF and verify the following:
Circuit 712 (to ground) remains 24 volts for ap-
proximately 5 minutes. After 5 minutes, the voltage
drops to 0.
The 5 minute idle indicator lamp on the overhead
display is ON when circuit 712 reads 24 volts.
3. Repeat step 1. While monitoring voltage at circuit
712, turn the key switch OFF. Push the engine
shutdown switch off.
Verify voltage at circuit 712 drops to 0 when the
shutdown switch is pushed to OFF.
INCLINOMETER
The inclinometer is used by the on-board load weigh-
ing system to determine whether the truck is on a level
surface or tilted fore or aft. The information provided
by the inclinometer is sent to the weighing system for
use in calculating the payload. Refer to Section M for
detailed information on the inclinometer and on board
load weighing system.
D03019 04/01
BRAKE WARNING BUZZER (BWB)
The brake warning buzzer (11) provides an audible
alarm for the operator if a malfunction occurs in the
hydraulic service brake system. Refer to Section J for
additional operational details.
ALARM INDICATING DEVICE (AID) SYSTEM
The Alarm Indicating Device (16, Figure 3-1) used on
Haulpak trucks is a device which is connected in the
electrical accessories circuits to provide the operator
with a warning indication of a malfunction. This system
consists of up to eight printed circuit cards, located
under the passenger seat in the operators cab. The
actual quantity of cards will depend on options installed
on the truck.
The AID system enables the indicating lights to be
flashing or constant. The AID also has the capability of
operating an audible alarm along with the light. The
eight printed circuit cards are (refer to Figure 3-2):
• Diode Matrix (With Sound) Card (Slot 1)
• Diode Matrix (Without Sound) Card (Slot 2)
• Hot Switch Inverter Card (Slot 3)
• Hot Switch Inverter Card (Slot 4) (Not Used)
• Temperature Card (Slot 5) (Not Used)
• Oil Level Card (Slot 6)
• Temperature and Latch Card (Slot 7)
• Coolant Level and Flasher Card (Slot 8)
NOTE: Each card is identified with a number which
corresponds with a mating number on the housing. If
cards are removed, make sure card numbers corre-
spond with housing numbers during installation (See
Figure 3-2).
The following briefly describes each card and its func-
tion. Refer to Section "R" for circuit components de-
scribed below.
Coolant Level/Flasher
The Coolant Level and Flasher Card contains two sepa-
rate circuits. The flasher circuit at the top of the card
has Q12 transistor biased to be saturated when no
malfunction is present, resulting in there being 24 volt
positive output on pin "H" of the card and on wire 12F.
When a indicating circuit is activated, the ground side
of the circuit connected to card pin "K" is grounded.
Q12 will turn off initially and then after a delay, adjusted
by R20, will turn on and off to give the intermittent 24
volt output.
24VDC System Components
D3-3
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Troubleshooting
