TM-9-2320-285-24-1

TRUCK TRACTOR, YARD TYPE, 43,500 LB GVW, DED, 4X2, ARMY MODEL M878A1

TECHNICAL MANUAL; ORGANIZATIONAL, DIRECT SUPPORT AND GENERAL SUPPORT MAINTENANCE MANUAL

OCTOBER 1985
TM-9-2320-285-24-1

  TM-9-2320-285-24-1 - Page 19 of 987

TM 9-2320-285-24-1
1-20.
ELECTRICAL SYSTEM (CONT)
b.
Instrument Panel Switches and Gage Lights (cont).
1.
IGNITION SWITCH.
Three position switch applies power to vehicle electrical circuits.
Turned to first clockwise
detent position, applies power to all circuits except engine starter.
2.
QUICK START SWITCH.
Aids cold-weather starting; injects ether into air intake system.
3.
ENGINE STOP SWITCH.
Controls fuel shut-off solenoid on engine governor; stops fuel flow to engine.
4.
HEADLIGHT SWITCH.
Two position switch controls headlights and dash, gage, side marker, and parking lights;
controls brightness of dash and gage lights.
With trailer lighting cable connected, also controls trailer parking and side
marker lights.
5.
FLOOD LIGHT SWITCHES.
Three independent switches control vehicle floodlights.
6.
BLOWER SWITCH.
Controls speed of cab heater fan.
7.
TRAILER LIGHT SWITCH.
With trailer lighting cable connected to 12 volt trailer, controls trailer interior lights.
8.
24V INVERTER SWITCH.
Turns on 24 volt inverter to allow 24 volt trailer lighting cable to power 24 volt trailer.
9.
WASHER BUTTON.
Applies two streams of washing solvent to windshield.
10.
WIPER CONTROL.
Operates windshield wiper blade and speed of wiper.
11.
TEMPERATURE CONTROL.
Regulates amount of hot water flowing to cab heater.
12.
DEFROSTER CONTROL.
Allows heated air from cab heater to be directed through windshield defroster vents to
windshield.
13.
FRESH AIR CONTROL.
Regulates amount of outside air applied to cab heater.
14.
GAGE LIGHTS.
Eight socket and bulb assemblies controlled by headlight switch.
1-21.
TRANSMISSION AND PROPELLER SHAFT
1.
TORQUE CONVERTER.
Integral part of
transmission; transmits and multiplies engine power.
2.
TRANSMISSION.
Automatic
transmission
provides five forward speeds and one reverse speed;
includes torque converter, shift lockout cylinder, and
control valve.
Mechanical lock-out prevents shifting to or
from reverse unless brake treadle is depressed.
3.
CONTROL VALVE.
Directs oil under pressure
to the desired directional and speed clutch.
4.
PROPELLER SHAFT.
Telescoping tube with
universal joint at each end; connects transmission and
rear axle
differential.
1-10


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