TROUBLESHOOTING THE HMMWV - OD1616 - LESSON 1/TASK 2
for cranking the engine with an electric motor was developed as
automotive technology progressed.
The modern electric starting
to the turn of a key or the pushing of a button.
The starter may
drive the engine through a pinion or by a dog clutch attached to the
starter armature shaft. The shaft is brought together with the teeth
cut on the rim of the flywheel or with the mating half of the dog
The drive must be equipped with an overrunning clutch or
some other means of quick disengagement.
Owing to limitations of
size and capacity of the battery, a high-speed starter with a high
gear reduction is used to obtain the necessary torque.
speed reduction required is affected in the majority of cases by
using the flywheel as a driven gear. In some instances, the gear is
bolted or shrunk on the flywheel; while in others, the gear teeth are
cut directly in the rim of the flywheel itself.
The starter is
mounted on the flywheel housing.
The starter used on the HMMWV is a 24 Volt unit activated by the
RUN/START switch through a solenoid mounted on the starter motor
The switch is placed to the RUN position and the WAIT TO
START lamp illuminates. A relay in the protective control box (PCB)
energizes the glow plugs and after approximately six seconds, the
WAIT TO START lamp will extinguish. The vehicle may now be started
by positioning the switch to the START position.
The starter will
engage the crank and the engine. Releasing the switch allows it to
return to the RUN position.
In other words, the switch is spring-
loaded to the RUN position. An ac output from the alternator to the
PCB prevents the starter from re-engaging once the engine is running.
A neutral (safety) switch mounted in the transmission quadrant
prevents the vehicle from being started in any gear other than
(4) Wiring Design. The vehicle wiring design uses a harness-type
construction and a modular approach that separates the harness into
four major sub-assemblies.
These sub-assemblies are: engine, body,
hood. These harnesses have multi-circuit disconnects for removal of
the major assemblies for maintenance.