another so that logic will not necessarily uncover both.
a. The symbols used in the troubleshooting
A short circuit condition, for instance, will in many cases
routines have definite meanings. Diamonds enclose
be manifested as an open circuit breaker. Replacement
"Yes" or "No" questions, rectangles enclose special
of the circuit breaker will not eliminate the short circuit
instructions, and circles enclose problem solutions
condition. The mechanic has a responsibility to visually
(conclusions) or continuation references to other
inspect harnesses for obvious conditions such as frayed
routines.
insulation or severed conductors and make necessary
b. Each troubleshooting routine has a
repairs prior to troubleshooting.
The same
schematic diagram reference (s) keyed to it. The
troubleshooting routine may have to be used more than
harness-to-view index (electrical system only) lists the
once.
The user should not be discouraged from
harness numbers on schematic diagram in numerical
searching for two or more interacting faults. Such
order. Next to each harness number is a locational view
malfunctions present the problems which can only be
reference and related circuit numbers.
countered by a ready knowledge of the vehicle and
c. In troubleshooting routines, there are many
systems, and a general troubleshooting "know how."
questions (enclosed in diamonds) that carry implicit
Reliance is often placed on the skill of the mechanic to
actions using standard operating procedures For
pinpoint the actual fault from a general localization of
example, a question such as "Will electromagnetic
possible faults.
clutch operate?" implies that the mechanic must
f.
activate the control switch to see if the electromagnetic
loading required to detect poor conductance. If a circuit
clutch will operate.
were loaded, the voltage or loss of voltage is assumed
d. The conclusions in the troubleshooting
to be at the point of measurement To preclude
routines (enclosed in circles) specify the corrective
misleading indications, the circuit under test should be
action that should be taken. In reaching a conclusion,
loaded as would be the case if a test lamp were
the part most likely to have failed is noted. This
employed.
conclusion does not eliminate the possibility that
g. In high current circuits such as the starter,
associated components (as wiring to the part) may be at
generator and battery, the necessity of almost perfect
fault. With a conclusion such as "Repair/Replace
Electromagnetic Clutch," the mechanic has a
check all connections, especially connector pins and
responsibility to check the complete hook-up of the
sockets. Components terminal must be clean, bright,
wiring and mechanical attachments and make
and bonded securely. A fraction of an ohm resistance at
necessary repair. Repair implies that action is needed
a connection not measurable with an ohmmeter can
to put the part back in service as dictated by the
cause malfunction.
Maintenance Allocation Chart. This may include a
complete replacement of authorized components by any
action required.
e. The limitation of the troubleshooting
routine is important to recognize. One fault may cause
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