secondary winding is checked by connecting the ohmmeter
to the coil case and to the high-voltage center tower. Again,
an infinite reading indicates an open winding; if any reading
is obtained, it indicates a shorted winding. Be sure to use the
middle- or high-resistance range of the ohmmeter when you
check the continuity of the secondary winding.
5. Check the operation of the ignition pulse
amplifier by detaching the positive and negative leads
from the coil and connecting them in series to a 12-volt,
6. Crank the engine and observe the bulb. If it flickers
on and off, the amplifier is operating properly. If the bulb
does not flicker on and off, check the distributor.
7. Connect a vacuum source to the distributor and an
ohmmeter to the two terminals on the distributor
connector. Open the vacuum source to the distributor, and
observe the ohmmeter throughout the range of the vacuum
source. A reading less than 550 ohms or more than 750
ohms indicates a defective pickup coil in the distribute.
8. Remove one ohmmeter lead from the distributor
connector and ground it. Again, open the vacuum source
to the distributor as you observe the ohmmeter. A reading
less than infinite indicates a defective pickup coil.
ELECTRONIC IGNITION SYSTEM
Provided the engine analyzer is not available, you
may troubleshoot the electronic ignition system to
prevent unnecessary replacement of its expensive units.
(See table 4-1.) You will need a volt/ohmmeter with a
20,000 volt/ohm range. Check the battery in the system
being tested; battery voltage must beat least 12 volts.
Make sure the ignition switch is off when the
control unit connector is being removed or
Disconnect the wiring plug from the control unit,
and turn on the ignition switch. Ground the negative
voltmeter lead. Connect the positive voltmeter lead to
the harness cavities designated in the sequence
recommended by the manufacturer. Voltage should be
within 1 volt of battery voltage with all accessories off.
If not, check that circuit through to the battery. Turn the
ignition switch off after completing the voltage test.
Connect the ohmmeter to the cavities designated. If
resistance is not within the manufacturers range,
disconnect the dual lead connector from the distributor.
Recheck resistance at the dual lead connector. With one
ohmmeter lead still grounded, connect the other lead to
either distributor connector. If the ohmmeter shows a
reading, replace the distributor pickup coil. To test for
control unit continuity, ground one ohmmeter lead and
connect the other lead to the control unit pin designated.
If continuity cannot be obtained after removing and
remounting the control unit in an attempt to get good
ground, replace the control unit. Make sure the ignition
switch is OFF, and reconnect the control unit connector
plug and the distributor plug. Check the air gap
adjustment as described previously. After these tests or
repairs, test the entire system by removing the center
wire from the distributor cap. Using insulated pliers and
a heavy rubber glove, hold this wire about one-half of
an inch from the engine block and operate the starter. If
there is no spark replace the control unit and retest. If
no spark is obtained, replace the coil.
SYSTEMS AND ELECTRICAL
Most modern automotive and construction vehicles
(Military Tactical CESE included) have up to 60 or 70
lights and numerous electrical accessories, such as small
motors, gauges, solenoids, and switches. Each one of
these devices presents a new troubleshooting problem
to the CM1. To perform these tests, you need a few
simple hand tools, such as screwdrivers, pliers, a 12/24
volt test lamp, and most important, a volt/ohmmeter
(fig. 4-42). For routine testing of burned out light bulbs,
Figure 4-42.-Typical volt/ohmmeter.