TM-9-2320-272-10

TRUCK, 5-TON, 6X6, M939, M939A1, AND M939A2 SERIES TRUCKS (DIESEL)

TECHNICAL MANUAL; OPERATOR'S MANUAL

SEPTEMBER 2004

CHANGE 2

TM-9-2320-272-10 - Page 101 of 481

Key

Item and Function

1

AIR CLEANER INDICATOR shows red when engine air filter needs servicing.

2

PARKING BRAKE WARNING LIGHT lights when parking brake is on.

3

LOW AIR PRESSURE WARNING LIGHT illuminates when air brake

system pressure drops below 50-60 psi (345-414 kPa).

4

SPRING BRAKE WARNING LIGHT lights when spring brakes are

engaged.

5

LOW COOLANT LEVEL LIGHT (M939A2 series vehicles) lights when

engine coolant level is low.

6

AXLE LOCK-IN LIGHT lights when front wheel drive lock-in switch is on.

7

HIGH BEAM INDICATOR lights when front headlights are on high beam.

8

HAND THROTTLE CONTROL sets engine speed at desired rpm without

maintaining pressure on accelerator pedal. Throttle control locks in desired

position when pulled out. Rotating control handle clockwise or counter—

clockwise unlocks it.

9

BATTERY SWITCH activates and deactivates all electrical circuits on or off

except arctic heater and lights.

10

IGNITION SWITCH has OFF, RUN, and START positions. Switch auto-

matically returns from START to RUN when hand pressure is released.

11

TACHOMETER indicates engine speed in revolutions per minute (rpm) and

operating hours in tenths.

12

SPEEDOMETER/ODOMETER indicates vehicle speed and total mileage.

13

ENGINE COOLANT TEMPERATURE GAUGE indicates engine coolant temper-

ature. Normal engine coolant operating temperature for M939/A1 series vehicles is

175°-195°F (79°-91°C) and 190°-200°F (88°-93°C) for M939A2 series vehicles.

TM 9-2320-272-10

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Change 2

2-3. CHASSIS CONTROLS AND INDICATORS