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TM 9-2330-398-24
2-14.
ELECTRICAL TROUBLESHOOTING (continued).
WARNING
Throughout troubleshooting of the electrical system or electrical components, be
certain MASTER switch Is OFF between every step unless otherwise. directed. To /
prevent Injury due to electrical shock, remove all jewelry and metal objects when
working on the electrical system.
c.
The multimeter is used throughout electrical troubleshooting. When using the multimeter, make sure it is used
with a probe kit.
d.
When performing a shorts test, make sure all connectors and/or leads are disconnected from their components.
Probe the pins (or sockets) with a multimeter. This is done by placing the red lead on pin (or socket) A (or 1) and
then placing the black lead on the next pin (or socket) in alphabetical (or numerical) order. Probe every pin (or
socket) on the connector or lead with the black lead of the multimeter.
e.
When probing has been completed, place the red lead on the second pin (or connector) and do the probing with
the black lead in order again. Do this until every pin has been probed with the red lead of the multimeter. Then
place the black lead of the multimeter on the connector and place the red lead on each pin (or socket) on the
connector.
f.
If continuity is present between any two points, a short exists. Shorts must be repaired in order to continue any
operation.
g.
If instructed in a procedure to skip a pin (or socket) during a shorts test, it is because the pin (or socket) is not
used / or is shielded.
h.
When a repair or replacement of a lead or wiring harness has been done, do the shorts test again to make sure
the problem has been corrected.
i.
When performing a continuity check, connect the meter probes to both terminals of the circuit you are testing.
Read the meter. Interpret the results. If the needle swings over to near 0 on the top scale, the circuit has
continuity. If the needle does not move, the circuit is open. If the needle jumps or flickers, there is a loose
connection.
j.
Check light bulbs for cracks or discoloration. Check the continuity of a light bulb by placing one probe of the meter
on the metal button base connection of the bulb and one probe on the metal side of the base. If the meter needle
swings over to 0 on the top scale, the circuit has continuity. If the meter needle does not move, the circuit is open,
indicating a defect.
2-15
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