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 69 of 481
TM 9-2320-272-10
1-52
1-19. ELECTRICAL SYSTEMS OPERATION (Contd)
e. Directional Signal System Operation.
The directional signal system is identical on all models covered in this manual
and consists of the following major components and circuitry:
A
FRONT COMPOSITE LAMP
– Receives power from turn signal control
through circuits 460 and 461 to indicate turning direction.
B
LIGHT SWITCH
– Provides battery power to the directional signal switch
through circuits 460 and 461, and to the stoplight switch through circuit 75.
C
STOPLIGHT SWITCH
– Closing this switch allows power to flow from the
light switch through circuit 75 to circuit 22 to the directional signal switch.
E
DIRECTIONAL SIGNAL SWITCH
– A four-position switch that directs
power to the composite and signal lamps through circuits 460, 461, 22-460,
and 22-461 to indicate direction of turn.
D
REAR COMPOSITE LAMP
– Receives power from turn signal control
through circuit 22-460 and 22-461 to indicate turning direction.
F
TURN SIGNAL FLASHER
– Receives power through circuit 467A and
sends intermittent current to the signal lamp through circuit 467B.
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