TM 9-2320-280-20-1
VEHICLE
BATTERIES
STARTER
SOLENOID
STARTER
ENGINE
MECHANICAL
PROTECTIVE CONTROL BOX/
DISTRIBUTION BOX
ROTARY
SWITCH
NEUTRAL
SAFETY
SWITCH
GENERAL DESCRIPTION
The Starter Circuit consists of the batteries, starter solenoid, starter motor, rotary switch,
neutral safety switch, protective control box/distribution box, and related electrical wiring. The
relationship of these parts is shown in the block diagram above, and a simplified functional flow
schematic is provided on the foldout FO-8.
The starter solenoid and starter motor are enclosed in housings to protect them from dirt, icing
conditions, and other road hazards.
When the rotary switch is turned to “START,” the starter solenoid is energized. The solenoid
contacts close, sending battery power to the starter motor. The battery power causes the
starter motor pinion gear to engage the engine flywheel ring gear and the engine cranks. When
the engine starts, the rotary switch should be released, allowing it to return to the “RUN”
position. This deenergizes the starter solenoid which, in turn, disengages the starter motor
from the engine.
Solenoid current flows from the rotary switch through the neutral safety switch and protective
control box/distribution box to the solenoid.
Change 1 2-261
STARTER CIRCUIT WITHOUT STARTER LOCKOUT
2-30. STARTER CIRCUIT TESTS
