1-1. INTRODUCTION
1-2. PURPOSE.
The purpose of this manual is to
provide diagnostic procedures that can be used for
troubleshooting a heavy-duty electrical system,
consisting of the starting system and the charging
system. Some of the procedures described in this
manual may also be used for preventative maintenance
checks. These procedures are applicable to systems
using Heavy Duty Starters such as: Delco Remy 37 MT,
41 MT, 42 MT, 50 MT or similar with adequate battery
power for the engine/starter application used.
1-3. DEFINITION OF “DIAGNOSIS.”
Diagnosis is
the three part process that begins when a problem is
perceived and ends when the equipment is confirmed
as serviceable. The process can be described by using
three questions that must be answered to assure
completion:
1. What are the symptoms? This is what has been
observed (seen, heard, felt or smelled) that indicates a
problem.
2. What caused the symptoms? This involves
using diagnostic procedures to identify the root cause
of the problem.
3. How do we fix it? Usually this involves the
adjustment, repair or replacement of some part or parts.
1-4.
The primary emphasis of this manual is to define
the procedures to determine “what caused the
symptoms.” Actual adjustment, repair or replacement
procedures are provided in unit specific service bulletins
and manuals.
1-5.
For educational purposes, study of this entire
manual is recommended. For diagnostic purposes, the
flow charts in Section II will reference appropriate
procedures for specific symptoms.
1-6. EQUIPMENT REQUIRED.
To perform the
tests specified in this manual, the following equipment
is required:
1. A variable carbon pile load tester, more than
500 amps capacity with ammeter (and voltmeter).
2. A separate DC voltmeter, digital preferred,
capable of reading 0.01 volt increments.
3. An inductive (clamp-on) ammeter for safe and
accurate current measurements.
1-7. DESCRIPTION
1-8. SYSTEM.
The heavy-duty electrical system is
made up of the starting system and the charging
system. These systems are, in turn, comprised of
batteries,
the starter,
the alternator,
the
interconnecting wiring and electrical and mechanical
switches. For maximum operating efficiency,
all
parts
of the system must be functioning properly.
Section I
INTRODUCTION AND DESCRIPTION
1-1
1. BATTERY
2. STARTER
3. ALTERNATOR
4. MAGNETIC SWITCH
5. PUSH BUTTON SWITCH
6. KEY SWITCH
1
2
3
4
5
6
Figure 1-1. Heavy Duty Electrical System
DP-1001
new diagnostic manual 4/5/05 9:47 AM Page 1-1
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